JP4897034B2 - BAR-LIKE STRUCTURE LIGHT EMITTING DEVICE, LIGHT EMITTING DEVICE, LIGHT EMITTING DEVICE MANUFACTURING METHOD, BACKLIGHT, LIGHTING DEVICE, AND DISPLAY DEVICE - Google Patents

Description

  The present invention relates to a rod-shaped structure light emitting element, a light emitting device, a method for manufacturing the light emitting device, a backlight, a lighting device, and a display device.

  Conventionally, as a light emitting element having a rod-shaped structure, there is a nano-order size light-emitting element in which a heterostructure is formed by a rod-shaped core portion made of a compound semiconductor and a cylindrical shell portion made of a compound semiconductor surrounding the core portion (for example, JP, 2008-235443, A (patent documents 1) reference). In this light emitting device, the core part itself becomes an active layer, and electrons and holes injected from the outer peripheral surface recombine in the core part to emit light.

  Using a manufacturing method similar to that of the light-emitting element, a pn junction between the outer peripheral surface of the core portion and the inner peripheral surface of the shell portion has a core portion made of an n-type semiconductor and a shell portion made of a p-type semiconductor. In the case of manufacturing a rod-shaped structure light emitting device that emits light by recombination of electrons and holes, there is a problem that it is difficult to connect the core portion and the electrode because only the both end surfaces are exposed.

JP 2008-235443 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fine rod-shaped structure light emitting element with high light emission efficiency that can easily connect electrodes with a simple configuration.

  Another object of the present invention is to provide a light emitting device that can be reduced in thickness and weight by using the light emitting element with a rod-like structure, has high luminous efficiency, and saves power, and a method for manufacturing the same.

  Another object of the present invention is to provide a backlight, an illuminating device, and a display device that can be reduced in thickness and weight by using the rod-shaped structure light emitting element, have high luminous efficiency, and save power.

In order to solve the above problems, the rod-shaped structure light emitting device of the present invention is
A rod-shaped first conductive type semiconductor core;
A semiconductor layer of a second conductivity type that covers a portion other than the exposed portion of the semiconductor core so as not to cover a portion on one end side of the semiconductor core,
Rutotomoni provided with an outer peripheral surface of the exposed portion not covered with the semiconductor layer of the semiconductor core, the stepped portion between the outer peripheral surface of the covering portion which is covered with the semiconductor layer of the semiconductor core,
The outer peripheral length of the cross section orthogonal to the longitudinal direction of the exposed portion of the semiconductor core is shorter than the outer peripheral length of the cross section orthogonal to the longitudinal direction of the covered portion of the semiconductor core .

  According to the above configuration, the covering portion other than the exposed portion of the semiconductor core is covered with the second conductive type semiconductor layer so that the portion on one end side of the rod-shaped first conductive type semiconductor core is not covered and is exposed. Therefore, even in the case of micro-order or nano-order sized fine rod-shaped light emitting devices, the exposed part of the semiconductor core is connected to one electrode, and the other electrode is connected to the semiconductor layer covering the coated part of the semiconductor core It becomes possible to do. In this rod-shaped structure light emitting device, one electrode is connected to the exposed portion of the semiconductor core, the other electrode is connected to the semiconductor layer, and the interface between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer (pn junction portion) ), A light is emitted from the interface (pn junction) between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer. In this rod-shaped structure light emitting element, the light emitting region is widened by emitting light from the entire side surface of the semiconductor core covered with the semiconductor layer, so that the light emission efficiency is high. A quantum well layer may be provided between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer.

  Therefore, it is possible to realize a fine rod-shaped light emitting element with high luminous efficiency that can be easily connected to an electrode with a simple configuration. Since this rod-shaped structure light emitting element is not integrated with the substrate, the degree of freedom of mounting on the device is high.

  Further, an exposed portion of the semiconductor core is provided by providing a step portion between the outer peripheral surface of the exposed portion of the semiconductor core not covered with the semiconductor layer and the outer peripheral surface of the covered portion of the semiconductor core covered with the semiconductor layer. The position of the end face of the semiconductor layer is determined by the stepped portion formed at the boundary between the exposed portion of the semiconductor core and the semiconductor layer, as compared with the case where the outer peripheral surface of the cover portion and the outer peripheral surface of the covering portion coincide with each other without a step. Variations in the boundary position can be suppressed during manufacturing. Here, the exposed portion of the semiconductor core may have a smaller diameter or a larger diameter than the covering portion. In addition, since the stepped portion can increase the distance between the outer peripheral surface of the exposed portion of the semiconductor core and the semiconductor layer, a short circuit between the electrode and the semiconductor layer when the electrode is connected to the exposed portion of the semiconductor core. And leakage current can be suppressed. In addition, light can be easily extracted from the stepped portion formed at the boundary between the outer peripheral surface of the exposed portion of the semiconductor core and the outer peripheral surface of the covering portion, so that the light extraction efficiency is improved. Furthermore, when the diameter of the exposed portion is larger than the covered portion of the semiconductor core, the contact surface with the electrode connected to the exposed portion of the semiconductor core can be made large, so that the contact resistance can be lowered.

  Here, the fine rod-shaped structure light-emitting element is, for example, a micro-order size having a diameter of 1 μm and a length of 10 μm, or a nano-order size element having a diameter or length of less than 1 μm. Further, the rod-shaped structure light-emitting element can reduce the amount of semiconductors used, can reduce the thickness and weight of the device using the light-emitting element, and has high luminous efficiency and low power consumption, a backlight, a lighting device, and A display device or the like can be realized.

In addition , the electrode is connected to the exposed portion of the semiconductor core because the outer peripheral length of the cross section orthogonal to the longitudinal direction of the exposed portion of the semiconductor core is shorter than the outer peripheral length of the cross section orthogonal to the longitudinal direction of the coated portion of the semiconductor core. In this case, the outer diameter of the semiconductor layer in the exposed portion of the semiconductor core is smaller than the outer diameter of the covering portion covered with the semiconductor layer of the semiconductor core, so that it is erected on the substrate in the manufacturing process. By providing the exposed portion of the formed semiconductor core on the substrate side, the semiconductor core is easily broken, and manufacturing is facilitated. In addition, since the exposed portion of the semiconductor core is on the lower side of the step portion (the semiconductor layer side is higher), the distance between the outer peripheral surface of the exposed portion of the semiconductor core and the semiconductor layer can be increased. When an electrode is connected to the exposed portion, it is possible to suppress the occurrence of a short circuit or leakage current between the electrode and the semiconductor layer. The cross-sections of the exposed portion and the covering portion of the semiconductor core are not limited to a circular shape, but may be other polygonal cross-sectional shapes such as a hexagon, and the exposed portion and the covering portion of the semiconductor core Different cross-sectional shapes may be used, and the same effect can be obtained if the exposed portion has a smaller diameter than the coated portion of the semiconductor core.

In addition, since the outer shape of the exposed portion of the semiconductor core is smaller than the outer shape of the semiconductor layer at least in the covered portion of the semiconductor core covered with the semiconductor layer, the rod-shaped structure light emitting element is elongated on the substrate with respect to the substrate plane. When mounting so that the directions are parallel, the outer peripheral surface of the semiconductor layer and the substrate can be easily contacted, and the heat dissipation efficiency is improved.
The rod-shaped structure light emitting device of the present invention is
A rod-shaped first conductive type semiconductor core;
A second-conductivity-type semiconductor layer covering a portion other than the exposed portion of the semiconductor core so as not to cover a portion on one end side of the semiconductor core;
With
Providing a step between the outer peripheral surface of the exposed portion of the semiconductor core that is not covered by the semiconductor layer and the outer peripheral surface of the covering portion of the semiconductor core that is covered by the semiconductor layer;
A shape of a cross section orthogonal to the longitudinal direction of the exposed portion of the semiconductor core is different from a shape of a cross section orthogonal to the longitudinal direction of the covered portion of the semiconductor core.
According to the above configuration, the covering portion other than the exposed portion of the semiconductor core is covered with the second conductive type semiconductor layer so that the portion on one end side of the rod-shaped first conductive type semiconductor core is not covered and is exposed. Therefore, even in the case of micro-order or nano-order sized fine rod-shaped light emitting devices, the exposed part of the semiconductor core is connected to one electrode, and the other electrode is connected to the semiconductor layer covering the coated part of the semiconductor core It becomes possible to do. In this rod-shaped structure light emitting device, one electrode is connected to the exposed portion of the semiconductor core, the other electrode is connected to the semiconductor layer, and the interface between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer (pn junction portion) ), A light is emitted from the interface (pn junction) between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer. In this rod-shaped structure light emitting element, the light emitting region is widened by emitting light from the entire side surface of the semiconductor core covered with the semiconductor layer, so that the light emission efficiency is high. A quantum well layer may be provided between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer.
Therefore, it is possible to realize a fine rod-shaped light emitting element with high luminous efficiency that can be easily connected to an electrode with a simple configuration. Since this rod-shaped structure light emitting element is not integrated with the substrate, the degree of freedom of mounting on the device is high.
Further, an exposed portion of the semiconductor core is provided by providing a step portion between the outer peripheral surface of the exposed portion of the semiconductor core not covered with the semiconductor layer and the outer peripheral surface of the covered portion of the semiconductor core covered with the semiconductor layer. The position of the end face of the semiconductor layer is determined by the stepped portion formed at the boundary between the exposed portion of the semiconductor core and the semiconductor layer, as compared with the case where the outer peripheral surface of the cover portion and the outer peripheral surface of the covering portion coincide with each other without a step. Variations in the boundary position can be suppressed during manufacturing. Here, the exposed portion of the semiconductor core may have a smaller diameter or a larger diameter than the covering portion. In addition, since the stepped portion can increase the distance between the outer peripheral surface of the exposed portion of the semiconductor core and the semiconductor layer, a short circuit between the electrode and the semiconductor layer when the electrode is connected to the exposed portion of the semiconductor core. And leakage current can be suppressed. In addition, light can be easily extracted from the stepped portion formed at the boundary between the outer peripheral surface of the exposed portion of the semiconductor core and the outer peripheral surface of the covering portion, so that the light extraction efficiency is improved. Furthermore, when the diameter of the exposed portion is larger than the covered portion of the semiconductor core, the contact surface with the electrode connected to the exposed portion of the semiconductor core can be made large, so that the contact resistance can be lowered.
In addition, the shape of the cross section orthogonal to the longitudinal direction of the exposed portion of the semiconductor core is different from the shape of the cross section orthogonal to the longitudinal direction of the covered portion of the semiconductor core, so that the outer peripheral surface of the exposed portion of the semiconductor core and the covering portion Since the step portion is formed at the boundary with the outer peripheral surface, the light extraction efficiency to the outside is improved. In addition, compared to the case where the outer peripheral surface of the exposed portion of the semiconductor core is coincident with the outer peripheral surface of the covering portion and there is no step, the step portion formed at the boundary between the exposed portion of the semiconductor core and the semiconductor layer The position of the end face is determined, and variation in the boundary position can be suppressed during manufacturing.
The rod-shaped structure light emitting device of the present invention is
A rod-shaped first conductive type semiconductor core;
A second-conductivity-type semiconductor layer covering a portion other than the exposed portion of the semiconductor core so as not to cover a portion on one end side of the semiconductor core;
With
Providing a step between the outer peripheral surface of the exposed portion of the semiconductor core that is not covered by the semiconductor layer and the outer peripheral surface of the covering portion of the semiconductor core that is covered by the semiconductor layer;
A cap layer formed to cover an end surface of the semiconductor core opposite to the exposed portion;
The cap layer is made of a material having a larger electric resistance than the semiconductor layer.
According to the above configuration, the covering portion other than the exposed portion of the semiconductor core is covered with the second conductive type semiconductor layer so that the portion on one end side of the rod-shaped first conductive type semiconductor core is not covered and is exposed. Therefore, even in the case of micro-order or nano-order sized fine rod-shaped light emitting devices, the exposed part of the semiconductor core is connected to one electrode, and the other electrode is connected to the semiconductor layer covering the coated part of the semiconductor core It becomes possible to do. In this rod-shaped structure light emitting device, one electrode is connected to the exposed portion of the semiconductor core, the other electrode is connected to the semiconductor layer, and the interface between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer (pn junction portion) ), A light is emitted from the interface (pn junction) between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer. In this rod-shaped structure light emitting element, the light emitting region is widened by emitting light from the entire side surface of the semiconductor core covered with the semiconductor layer, so that the light emission efficiency is high. A quantum well layer may be provided between the outer peripheral surface of the semiconductor core and the inner peripheral surface of the semiconductor layer.
Therefore, it is possible to realize a fine rod-shaped light emitting element with high luminous efficiency that can be easily connected to an electrode with a simple configuration. Since this rod-shaped structure light emitting element is not integrated with the substrate, the degree of freedom of mounting on the device is high.
Further, an exposed portion of the semiconductor core is provided by providing a step portion between the outer peripheral surface of the exposed portion of the semiconductor core not covered with the semiconductor layer and the outer peripheral surface of the covered portion of the semiconductor core covered with the semiconductor layer. The position of the end face of the semiconductor layer is determined by the stepped portion formed at the boundary between the exposed portion of the semiconductor core and the semiconductor layer, as compared with the case where the outer peripheral surface of the cover portion and the outer peripheral surface of the covering portion coincide with each other without a step. Variations in the boundary position can be suppressed during manufacturing. Here, the exposed portion of the semiconductor core may have a smaller diameter or a larger diameter than the covering portion. In addition, since the stepped portion can increase the distance between the outer peripheral surface of the exposed portion of the semiconductor core and the semiconductor layer, a short circuit between the electrode and the semiconductor layer when the electrode is connected to the exposed portion of the semiconductor core. And leakage current can be suppressed. In addition, light can be easily extracted from the stepped portion formed at the boundary between the outer peripheral surface of the exposed portion of the semiconductor core and the outer peripheral surface of the covering portion, so that the light extraction efficiency is improved. Furthermore, when the diameter of the exposed portion is larger than the covered portion of the semiconductor core, the contact surface with the electrode connected to the exposed portion of the semiconductor core can be made large, so that the contact resistance can be lowered.
In addition, the cap layer made of a material having a larger electric resistance than the semiconductor layer covers the end surface opposite to the exposed portion of the semiconductor core, so that the electrode connected to the cap layer side of the semiconductor core is between the semiconductor core and the semiconductor core. While preventing the current from flowing through the cap layer, the current is allowed to flow between the electrode and the outer peripheral surface side of the semiconductor core through the semiconductor layer having a lower resistance than the cap layer. This suppresses current concentration on the end surface of the semiconductor core where the cap layer is provided, and improves light extraction efficiency from the side surface of the semiconductor core without concentrating light emission on the end surface of the semiconductor core. To do.

Moreover, in the rod-shaped structure light emitting device of one embodiment,
The cross section orthogonal to the longitudinal direction of the covering portion of the semiconductor core is polygonal.

  According to the above embodiment, the rod-shaped structure light emitting element is mounted on the substrate so that the longitudinal direction thereof is parallel to the substrate plane because the cross section orthogonal to the longitudinal direction of the covering portion of the semiconductor core is polygonal. In this case, it is easy to obtain a contact surface with the substrate regardless of the outer peripheral surface of the semiconductor layer, and the heat dissipation efficiency to the substrate is improved. Therefore, it can suppress that the element temperature at the time of light emission raises, and luminous efficiency falls. In addition, the cross section perpendicular to the longitudinal direction of the exposed portion of the semiconductor core can improve the light extraction efficiency when the polygon (for example, hexagon) is more circular than the circular shape (the cross section of the exposed portion of the semiconductor core is the apex). The polygons with fewer numbers are more likely to emit light outside).

Moreover, in the rod-shaped structure light emitting device of one embodiment,
A cross section perpendicular to the longitudinal direction of the exposed portion of the semiconductor core is substantially circular.

  According to the above embodiment, the cross section orthogonal to the longitudinal direction of the exposed portion of the semiconductor core is substantially circular, so that the shape of the mask pattern used when growing the semiconductor core in the manufacturing process may be circular, and the plane of the substrate Manufacture is easy because there is no restriction on the mask layout aligned with the crystal orientation of the direction and the alignment accuracy for aligning the orientation is unnecessary.

Moreover, in the rod-shaped structure light emitting device of one embodiment,
An insulating layer is provided so as to cover the step portion of the semiconductor core and the end face of the semiconductor layer on the step portion side, and to cover the step portion side of the exposed portion of the semiconductor core.

  According to the above embodiment, the insulating layer is formed so as to cover the stepped portion of the semiconductor core and the end surface of the semiconductor layer on the stepped portion side, and to cover the stepped portion side of the exposed portion of the semiconductor core. Therefore, when the electrode is connected to the exposed part of the semiconductor core, the outer peripheral surface of the exposed part of the semiconductor core and the semiconductor layer can be insulated by the insulating layer. Generation can be reliably suppressed.

Moreover, in the rod-shaped structure light emitting device of one embodiment,
A conductive layer made of a material formed so as to cover the semiconductor layer and having an electric resistance lower than that of the semiconductor layer is provided.

  According to the above embodiment, by connecting the semiconductor layer to the electrode through the conductive layer made of a material having a lower electrical resistance than the semiconductor layer, current is not concentrated and biased in the electrode connection portion, and a wide current path The entire side surface of the semiconductor core can be made to emit light efficiently, and the luminous efficiency is further improved.

Moreover, in the rod-shaped structure light emitting device of one embodiment,
A quantum well layer is provided between the semiconductor core and the semiconductor layer.

  According to the embodiment, by forming the quantum well layer between the outer peripheral surface of the semiconductor core and the semiconductor layer, the light emission efficiency can be improved by the quantum confinement effect of the quantum well layer.

Moreover, in the rod-shaped structure light emitting device of one embodiment,
The diameter of the semiconductor core is 500 nm or more and 100 μm or less.

  According to the above embodiment, by setting the diameter of the semiconductor core to 500 nm or more and 100 μm or less, it is possible to suppress the variation in the diameter of the semiconductor core compared to the semiconductor core having a diameter of about several tens to several hundreds of nm. Thus, it is possible to realize a bar-shaped light emitting element with a high yield.

In the light emitting device of the present invention,
Any one of the above rod-shaped structure light emitting elements;
A substrate on which the rod-shaped structure light emitting element is mounted so that the longitudinal direction of the rod-shaped structure light emitting element is parallel to the mounting surface;
Electrodes are formed on the substrate at predetermined intervals,
The exposed portion on one end side of the semiconductor core of the rod-shaped structure light emitting element is connected to one electrode on the substrate, and the semiconductor on the other end side of the semiconductor core is connected to the other electrode on the substrate. It is characterized in that the layers are connected.

  According to the above configuration, the rod-shaped structure light emitting element mounted on the substrate so that the longitudinal direction is parallel to the mounting surface is generated in the rod-shaped structure light emitting element because the outer peripheral surface of the semiconductor layer and the mounting surface of the substrate are in contact with each other. Heat can be efficiently radiated from the semiconductor layer to the substrate. Therefore, a light emitting device with high luminous efficiency and good heat dissipation can be realized. Further, in the above light emitting device, since the rod-shaped structure light emitting elements are disposed on the substrate in a horizontal direction, the thickness including the substrate can be reduced. In the above light emitting device, for example, a semiconductor used by using a micro rod size light emitting element having a diameter of 1 μm and a length of 10 μm, or a nano-order size of a diameter or length of at least a diameter of less than 1 μm. Therefore, a backlight, a lighting device, a display device, and the like that can be reduced in thickness and weight can be realized by using the light emitting device.

In the light emitting device of one embodiment,
A rod-shaped structure light emitting device including a conductive layer formed so as to cover the semiconductor layer;
A substrate on which the rod-shaped structure light emitting element is mounted so that the longitudinal direction of the rod-shaped structure light emitting element is parallel to the mounting surface;
Electrodes are formed on the substrate at predetermined intervals,
The exposed portion on one end side of the semiconductor core of the rod-shaped structure light emitting element is connected to one of the electrodes on the substrate, and the conductive portion on the other end side of the semiconductor core is connected to the other electrode on the substrate. It is characterized in that the layers are connected.

  According to the above embodiment, the rod-shaped structure light-emitting element mounted on the substrate so that the longitudinal direction is parallel to the mounting surface is in contact with the outer peripheral surface of the conductive layer and the mounting surface of the substrate. The generated heat can be efficiently radiated from the conductive layer to the substrate. Therefore, a light emitting device with high luminous efficiency and good heat dissipation can be realized. Further, in the above light emitting device, since the rod-shaped structure light emitting elements are disposed on the substrate in a horizontal direction, the thickness including the substrate can be reduced. In the above light emitting device, for example, a semiconductor used by using a micro rod size light emitting element having a diameter of 1 μm and a length of 10 μm, or a nano-order size of a diameter or length of at least a diameter of less than 1 μm. Therefore, a backlight, a lighting device, a display device, and the like that can be reduced in thickness and weight can be realized by using the light emitting device.

In the light emitting device of one embodiment,
A second conductive layer made of a material having a lower electrical resistance than the semiconductor layer is provided on the conductive layer of the rod-shaped structure light emitting element and on the substrate side.

  According to the above embodiment, the second conductive layer made of a material having a lower electrical resistance than the semiconductor layer is formed on the conductive layer of the rod-shaped structured light-emitting element and on the substrate side, so that the rod-shaped structure without the second conductive layer is formed. Since there is a conductive layer covering the outer peripheral surface of the semiconductor core on the side opposite to the substrate of the structured light emitting device, the second conductive layer can be obtained without sacrificing the ease of current flow to the entire high resistance semiconductor layer. Can reduce the resistance. In addition, a low-resistance material cannot be used for the conductive layer covering the outer peripheral surface of the semiconductor core because a low-transmittance material cannot be used in consideration of light emission efficiency, but the second conductive layer has a transmittance. It is possible to use a conductive material that prioritizes low resistance. Further, in the rod-shaped structure light-emitting element mounted on the substrate so that the longitudinal direction is parallel to the mounting surface, the second conductive layer is in contact with the mounting surface of the substrate. Heat can be efficiently radiated to the substrate through the conductive layer.

In the light emitting device of one embodiment,
The metal part formed between the said electrodes on the said board | substrate and the lower side of the said rod-shaped structure light emitting element was provided.

  According to the above embodiment, by forming the metal part between the electrodes on the substrate and below the rod-like structure light emitting element, the center side of the rod-like structure light emitting element whose both ends are connected to the electrode is brought into contact with the surface of the metal part Since the two-sided rod-shaped structure light emitting element is supported by the metal part without being bent, the heat generated in the rod-shaped structure light emitting element is efficiently radiated from the semiconductor layer to the substrate through the metal part. Can do.

In the light emitting device of one embodiment,
The metal part is formed on the substrate for each of the rod-shaped structure light emitting elements,
The metal parts of the rod-shaped structure light emitting elements adjacent to each other are electrically insulated.

  According to the embodiment, even if the directions of the bar-shaped structure light emitting elements adjacent to each other are reversed, it is possible to prevent a short circuit between the electrodes to which both ends of the bar-shaped structure light emitting element are connected via the metal portion.

In the method for manufacturing a light emitting device of the present invention,
A method of manufacturing a light-emitting device including any one of the above rod-shaped structure light-emitting elements,
A substrate creating step for creating an insulating substrate in which an array region having at least two electrodes each having an independent potential applied thereto is formed;
An application step of applying a liquid containing the rod-shaped structure light emitting element of nano-order size or micro-order size on the insulating substrate;
And arranging the rod-shaped light emitting elements at positions defined by the at least two electrodes by applying the independent voltages to the at least two electrodes, respectively.

  According to the above configuration, an insulating substrate in which an array region having at least two electrodes each having an independent potential applied thereto is formed is formed, and the rod-shaped nano-order size or micro-order size is formed on the insulating substrate. A liquid containing the structured light emitting element is applied. Thereafter, independent voltages are applied to at least the two electrodes, respectively, so that the fine rod-shaped light emitting elements are arranged at positions defined by the at least two electrodes. Thereby, the said rod-shaped structure light emitting element can be easily arranged on a predetermined | prescribed board | substrate.

  Further, in the above method for manufacturing a light emitting device, by using only a fine rod-shaped structure light emitting element, it is possible to manufacture a light emitting device capable of reducing the amount of semiconductor used and reducing the thickness and weight. In addition, since the light emitting area is widened by emitting light from the entire side surface of the semiconductor core covered with the semiconductor layer, the rod-shaped structure light emitting element can realize a light emitting device with high luminous efficiency and power saving. .

In the backlight of the present invention,
Any one of the above rod-shaped structure light emitting elements is provided.

  According to the above configuration, by using the rod-shaped structure light emitting element, it is possible to realize a backlight that can be reduced in thickness and weight, has high luminous efficiency, and saves power.

In the lighting device of the present invention,
Any one of the above rod-shaped structure light emitting elements is provided.

  According to the said structure, by using the said rod-shaped structure light emitting element, thickness reduction and weight reduction are possible, and the illuminating device with high luminous efficiency and power saving is realizable.

In the display device of the present invention,
Any one of the above rod-shaped structure light emitting elements is provided.

  According to the above configuration, by using the light emitting element with a rod-like structure, a display device that can be reduced in thickness and weight and has high luminous efficiency and low power consumption can be realized.

  As is apparent from the above, according to the rod-shaped structure light emitting device of the present invention, it is possible to realize a fine rod-shaped structure light emitting device with high luminous efficiency that can be easily connected to an electrode with a simple configuration.

  Further, according to the light emitting device and the manufacturing method thereof of the present invention, it is possible to realize a light emitting device that can be reduced in thickness and weight, has high luminous efficiency, and saves power by using the rod-shaped structure light emitting element, and a manufacturing method thereof. Can do.

  In addition, according to the backlight, the illumination device, and the display device of the present invention, the backlight, the illumination device, and the display device that can be reduced in thickness and weight by using the rod-shaped structure light-emitting element and have high luminous efficiency and power saving. Can be realized.

FIG. 1 is a perspective view of a rod-shaped structure light emitting device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the rod-shaped structure light emitting device. FIG. 3 is a schematic cross-sectional view of the main part of a bar-shaped structure light emitting device of a comparative example. FIG. 4 is a schematic cross-sectional view of the main part of the rod-shaped structure light emitting device of the first embodiment. FIG. 5 is a cross-sectional view of a main part of a modification of the rod-shaped structure light emitting device of the first embodiment. FIG. 6 is a cross-sectional view of the main part for explaining electrode connection of the exposed portion of the semiconductor core of the rod-shaped structure light emitting device. FIG. 7 is a perspective view of a rod-shaped structure light emitting device according to a second embodiment of the present invention. FIG. 8 is a schematic cross-sectional view of the main part of the rod-shaped structure light emitting device of the second embodiment. FIG. 9A is a schematic cross-sectional view of an exposed portion of the semiconductor core of the rod-shaped structure light emitting device of the first embodiment. FIG. 9B is a schematic cross-sectional view of the exposed portion of the semiconductor core of the rod-shaped structure light emitting device of the second embodiment. FIG. 9C is a schematic cross-sectional view of an exposed portion of a semiconductor core of a rod-shaped structure light emitting element of a modification. FIG. 10 is a perspective view of a rod-shaped structure light emitting device according to a third embodiment of the present invention. FIG. 11 is a schematic cross-sectional view of a first modification of the rod-shaped structure light emitting device of the third embodiment. FIG. 12 is a schematic cross-sectional view of a second modification of the rod-shaped structure light emitting device of the third embodiment. FIG. 13 is a cross-sectional view of a rod-shaped structure light emitting device according to the fourth embodiment of the present invention. FIG. 14 is a perspective view of the rod-shaped structure light emitting element. FIG. 15 is a sectional view of a rod-shaped structure light emitting device according to the fifth embodiment of the present invention. FIG. 16 is a perspective view of the rod-shaped structure light emitting element. FIG. 17 is a perspective view of a rod-shaped structure light emitting device according to the sixth embodiment of the present invention. FIG. 18 is a perspective view of a rod-shaped structure light emitting device according to the seventh embodiment of the present invention. FIG. 19 is a sectional view of a rod-shaped structure light emitting device according to an eighth embodiment of the present invention. FIG. 20 is a schematic cross-sectional view of the main part of the rod-shaped structure light emitting device of the eighth embodiment. FIG. 21 is a perspective view of a light-emitting device provided with a rod-shaped structure light-emitting element according to the ninth embodiment of the present invention. FIG. 22 is a side view of a light emitting device including the rod-shaped structure light emitting element according to the tenth embodiment of the present invention. FIG. 23 is a cross-sectional view of the light emitting device. FIG. 24 is a perspective view of a light emitting device according to an eleventh embodiment of the present invention. FIG. 25 is a plan view of the main part of the light emitting device with the adjacent bar-shaped structure light emitting elements in the reverse direction. FIG. 26 is a plan view of an insulating substrate used in a light emitting device, a backlight, a lighting device, and a display device including a bar-shaped light emitting element according to a twelfth embodiment of the present invention. FIG. 27 is a schematic sectional view taken along line XXVII-XXVII in FIG. FIG. 28 is a diagram for explaining the principle of arranging the rod-shaped structure light emitting elements. FIG. 29 is a diagram for explaining the potential applied to the electrodes when arranging the rod-shaped structure light emitting elements. FIG. 30 is a plan view of an insulating substrate on which the rod-shaped structure light emitting elements are arranged. FIG. 31 is a plan view of the display device. FIG. 32 is a circuit diagram of a main part of the display unit of the display device.

  Hereinafter, the rod-shaped structure light emitting element, the light emitting device, the method for manufacturing the light emitting device, the backlight, the illumination device, and the display device of the present invention will be described in detail with reference to the illustrated embodiments. In this embodiment, the first conductivity type is n-type and the second conductivity type is p-type. However, the first conductivity type may be p-type and the second conductivity type may be n-type.

[First Embodiment]
FIG. 1 is a perspective view of a rod-shaped structure light emitting device according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the rod-shaped structure light emitting device.

  As shown in FIGS. 1 and 2, the rod-shaped structure light emitting device A of the first embodiment includes a semiconductor core 11 made of a rod-shaped n-type GaN having a substantially circular cross section, and a portion on one end side of the semiconductor core 11. A semiconductor layer 12 made of p-type GaN covering the covered portion 11b other than the exposed portion 11a of the semiconductor core 11 is provided so as to be the exposed portion 11a without being covered. In the semiconductor core 11, the exposed portion 11a has a smaller diameter than the covering portion 11b, and a step portion 11c is provided between the outer peripheral surface of the exposed portion 11a and the outer peripheral surface of the covering portion 11b. Further, the end surface on the other end side of the semiconductor core 11 is covered with the semiconductor layer 12.

  The rod-shaped structure light emitting device A is manufactured as follows.

First, a mask having a growth hole is formed on a substrate made of n-type GaN. For the mask, a material that can be selectively etched with respect to the semiconductor core 11 and the semiconductor layer 12 such as silicon oxide (SiO ₂ ) or silicon nitride (Si ₃ N ₄ ) is used. The growth hole can be formed by a known lithography method and dry etching method used in a normal semiconductor process.

  Next, a catalytic metal layer is formed on the substrate exposed by the growth holes of the mask. The catalytic metal layer is formed on the resist and the substrate exposed from the growth hole (on the exposed region in the growth hole) while leaving the resist used for the growth hole formation on the mask by the lithography method and the dry etching method. ) Is deposited by removing the catalyst metal layer on the resist together with the resist by a lift-off method. Ni, Fe, Au, etc. that dissolve and take in compound semiconductor materials such as Ga, N, In, Al and impurities such as Si, Mg, etc., and do not form compounds with themselves in the catalytic metal layer Can be used.

Next, using a MOCVD (Metal Organic Chemical Vapor Deposition) apparatus on the substrate having the catalytic metal layer formed in the growth hole of the mask, an n-type is formed from the interface between the catalytic metal layer and the substrate. GaN is crystal-grown to form a rod-shaped semiconductor core 11. The temperature of the MOCVD apparatus is set to about 950 ° C., trimethylgallium (TMG) and ammonia (NH ₃ ) are used as growth gases, silane (SiH ₃ ) is used for supplying n-type impurities, and hydrogen (H ₃ ), an n-type GaN semiconductor core having Si as an impurity can be grown. At this time, the diameter of the growing semiconductor core 11 is determined by the inner diameter of the growing hole because the diameter of the catalytic metal layer does not expand beyond the inner diameter of the growing hole in the growing hole of the mask. After the height exceeds the mask height (growth hole depth), it can be determined by the diameter of the catalyst metal layer that aggregates in an island shape. Therefore, when the catalytic metal layer is formed with the above film thickness, after the height of the growing semiconductor core 11 exceeds the height of the mask (the depth of the growth hole), the island shape has a larger diameter than the growth hole. Therefore, the covering portion 11b of the semiconductor core 11 can be grown with a diameter larger than the diameter of the exposed portion 11a of the semiconductor core 11 in the growth hole.

Next, a semiconductor layer made of p-type GaN is formed on the entire surface of the substrate so as to cover the rod-shaped semiconductor core 11 while the island-shaped catalyst metal layer is held at the tip of the semiconductor core 11. By setting the temperature of the MOCVD apparatus to about 960 ° C., using trimethylgallium (TMG) and ammonia (NH ₃ ) as growth gases and biscyclopentadienylmagnesium (Cp ₂ Mg) for supplying p-type impurities, It is possible to grow p-type GaN having (Mg) as an impurity.

  Next, the island-like catalytic metal layer is removed, and the region and mask other than the portion of the semiconductor layer that covers the semiconductor core are removed by lift-off to expose the outer peripheral surface of the rod-shaped semiconductor core 11 on the substrate side. To form an exposed portion. In this state, the end surface of the semiconductor core 11 opposite to the substrate is covered with the semiconductor layer 12, and an exposed portion 11a having a smaller diameter than the covered portion 11b of the semiconductor core 11 is formed.

When the mask is made of silicon oxide (SiO ₂ ) or silicon nitride (Si ₃ N ₄ ), a semiconductor layer and a semiconductor layer that easily covers the semiconductor core can be obtained by using a solution containing hydrofluoric acid (HF). The mask can be etched without affecting the portion, and the region other than the portion of the semiconductor layer covering the semiconductor core on the mask together with the mask can be removed by lift-off. In this embodiment, the length of the exposed portion 11a of the semiconductor core 11 is determined by the thickness of the removed mask. In the exposure process of this embodiment, lift-off is used, but a part of the semiconductor core may be exposed by etching.

  Next, the substrate is immersed in an isopropyl alcohol (IPA) aqueous solution, and the substrate is vibrated along the plane of the substrate using ultrasonic waves (for example, several tens of kHz). Stress is applied to the semiconductor core 11 covered with the semiconductor layer 12 so that the close base is bent, and the semiconductor core 11 covered with the semiconductor layer 12 is separated from the substrate.

  In this way, a fine rod-shaped structure light emitting device separated from the substrate made of n-type GaN can be manufactured.

  Moreover, although the said semiconductor core was cut off from the board | substrate using the ultrasonic wave, you may cut off by not only this but mechanically bending the semiconductor core from a board | substrate using a cutting tool. In this case, a plurality of fine rod-shaped light emitting elements provided on the substrate can be separated in a short time by a simple method.

  Furthermore, in the rod-shaped structure light emitting element, the semiconductor layer 12 grows crystal outward from the outer peripheral surface of the semiconductor core 11 in the radial direction, the radial growth distance is short, and the defects escape outward, so the semiconductor layer 12 with few crystal defects. Thus, the semiconductor core 11 can be covered. Therefore, it is possible to realize a rod-shaped structure light emitting device with good characteristics.

  According to the rod-shaped structure light emitting element A having the above-described configuration, the covering portion 11b other than the exposed portion 11a of the semiconductor core 11 is formed so as to be the exposed portion 11a without covering the portion on one end side of the rod-shaped n-type semiconductor core 11. By covering with the p-type semiconductor layer 12, the exposed portion 11 a of the semiconductor core 11 is connected to the n-side electrode to cover the semiconductor core 11 even in a micro rod-shaped or nano-order sized light emitting element. It becomes possible to connect the p-side electrode to the portion of the semiconductor layer 12. In this rod-shaped structure light emitting element A, an n-side electrode is connected to the exposed portion 11a of the semiconductor core 11, a p-side electrode is connected to the semiconductor layer 12, and a current flows from the p-side electrode to the n-side electrode. Electrons and holes are recombined at the interface (pn junction) between the outer peripheral surface of the core 11 and the inner peripheral surface of the semiconductor layer 12, and light is emitted. In this rod-shaped structure light-emitting element A, the light emission region is widened by emitting light from the entire side surface of the semiconductor core 11 covered with the semiconductor layer 12, so that the light emission efficiency is high.

  Therefore, it is possible to realize a fine rod-shaped light emitting element A with high luminous efficiency that can easily connect electrodes with a simple configuration. Moreover, since the said rod-shaped structure light emitting element A is not integral with a board | substrate, the freedom degree of mounting to an apparatus is high.

  Here, the fine rod-shaped structure light emitting device is, for example, a micro-order size having a diameter of 1 μm and a length of 10 μm to 30 μm, or a nano-order size device having a diameter or length of less than 1 μm. Further, the rod-shaped structure light-emitting element can reduce the amount of semiconductors used, can reduce the thickness and weight of the device using the light-emitting element, and has high luminous efficiency and low power consumption, a backlight, a lighting device, and A display device or the like can be realized.

  Further, when the outer peripheral surface on one end side of the semiconductor core 11 is exposed, for example, by about 1 μm to 5 μm, one n-side electrode is connected to the exposed portion 11 a of the outer peripheral surface on one end side of the semiconductor core 11, The p-side electrode can be connected to the semiconductor layer 12 on the other end side of the core 11, the electrodes can be separated from each other, and the p-side electrode connected to the semiconductor layer 12 and the exposed portion 11 a of the semiconductor core 11 are short-circuited. This can be easily prevented.

  FIG. 3 is a schematic cross-sectional view of the main part of the bar-shaped structure light emitting device of the comparative example, and is not the bar-shaped structure light emitting device of the present invention. 3 differs from the rod-shaped structure light emitting device A shown in FIGS. 1 and 2 of the first embodiment in that the outer peripheral surface of the exposed portion of the semiconductor core 1011 and the semiconductor layer 1012 of the semiconductor core 1011 are different. That is, there is no step between the covered portion and the covered portion.

  In this rod-shaped structure light emitting device, when the n-side electrode is connected to the exposed portion of the semiconductor core 1011, there is no stepped portion, and therefore the distance L between the n-side electrode 1013 and the end surface of the semiconductor layer 1012 becomes short, and the n-side electrode 1013. And a short circuit between the semiconductor layer 12 and a leakage current may occur. Further, in this rod-shaped structure light emitting element, as shown in FIG. 3, light having a large incident angle from the inside of the semiconductor core 1011 to the outer peripheral surface of the exposed portion is reflected inside the semiconductor core 1011 and is difficult to take out to the outside.

  On the other hand, as shown in the schematic cross-sectional view of FIG. 4, in the rod-like structure light emitting device shown in FIGS. 1 and 2 of the first embodiment, the semiconductor layer 12 of the semiconductor core 11 is formed as shown in FIG. By providing a step portion 11c between the outer peripheral surface of the uncovered exposed portion 11a and the outer peripheral surface of the covered portion of the semiconductor core 11 covered with the semiconductor layer 12, the outer peripheral surface of the exposed portion 11a of the semiconductor core 11 is provided. Compared with the comparative example of FIG. 3 in which the outer peripheral surface of the covering portion 11b coincides with that of the covering portion 11b, the step portion 11c formed at the boundary between the exposed portion 11a of the semiconductor core 11 and the semiconductor layer 12 The position of the end face is determined, and variations in the boundary position can be suppressed during manufacturing. When the outer peripheral surface of the exposed portion of the semiconductor core and the outer peripheral surface of the covering portion coincide with each other as in the comparative example of FIG. 3 and there is no step, the gap between the inner wall of the growth hole of the mask and the semiconductor core is increased during the growth of the semiconductor core. When a semiconductor layer is subsequently formed, the semiconductor layer is also formed in the gap region between the growth hole inner wall of the mask and the semiconductor core, and the semiconductor core is originally defined by the position of the upper surface of the mask. The boundary between the exposed portion and the covered portion may vary. On the other hand, when there is a step between the outer peripheral surface of the exposed portion of the semiconductor core and the outer peripheral surface of the covering portion as in the first embodiment shown in FIG. Since the semiconductor core is grown with a diameter larger than the inner diameter of the hole, even if a gap is formed between the inner wall of the growth hole of the mask and the semiconductor core, the semiconductor core grows so as to close the gap, and the semiconductor is formed when the semiconductor layer is formed. It is possible to prevent the layer from being formed in the gap region between the inner wall of the mask growth hole and the semiconductor core. In FIG. 4, even if the distance in the longitudinal direction between the n-side electrode 13 and the end face of the semiconductor layer 12 is the same, the distance increases in the radial direction by the step portion 11c.

  Further, the step portion 11c provided between the outer peripheral surface of the exposed portion 11a of the semiconductor core 11 and the outer peripheral surface of the covering portion 11b allows the distance between the outer peripheral surface of the exposed portion 11a of the semiconductor core 11 and the semiconductor layer 12 to be increased. Since the n-side electrode can be connected to the exposed portion 11 a of the semiconductor core 11, it is possible to suppress the occurrence of a short circuit or leakage current between the n-side electrode and the semiconductor layer 12. Furthermore, light can be easily extracted to the outside from the step portion 11c formed at the boundary between the outer peripheral surface of the exposed portion 11a of the semiconductor core 11 and the outer peripheral surface of the covering portion 11b, so that the light extraction efficiency is improved.

  FIG. 5 shows a cross-sectional view of a main part of a modification of the rod-shaped structure light emitting device of the first embodiment.

  In the rod-shaped structure light emitting element of this modification, the semiconductor core 15 has a stepped portion 15c between the outer peripheral surface of the exposed portion 15a and the outer peripheral surface of the covered portion 15b, with the exposed portion 15a having a larger diameter than the covered portion 15b. Provided. An n-side electrode 17 is connected to the exposed portion 15 a of the semiconductor core 15.

  As shown in FIG. 5, since the step portion 15c is formed at the boundary between the outer peripheral surface of the exposed portion 15a of the semiconductor core 15 and the outer peripheral surface of the covering portion 15b, the light extraction efficiency to the outside is improved. Moreover, since the diameter of the exposed portion 15a is larger than the covered portion 15b of the semiconductor core 15, the contact surface with the n-side electrode 17 connected to the exposed portion 15a of the semiconductor core 11 can be made large, so that the contact resistance is lowered. Can do.

  In addition, according to the rod-shaped structure light emitting element A of the first embodiment, it is orthogonal to the longitudinal direction of the exposed portion 11a of the semiconductor core 11 rather than the outer peripheral length of the cross section orthogonal to the longitudinal direction of the covered portion 11b of the semiconductor core 11. The exposure of the semiconductor core 11 formed to stand on the substrate in the manufacturing process by shortening the outer peripheral length of the cross section, that is, by exposing the exposed portion 11a to be smaller in diameter than the covering portion 11b of the semiconductor core 11. By providing the portion 11a on the substrate side, the semiconductor core 11 is easily broken, and the manufacture is facilitated. As already described, the semiconductor core 11 is separated from the substrate by vibrating with ultrasonic waves in IPA. However, the semiconductor core 11 is easily separated because the exposed portion 11a of the semiconductor core 11 is thin.

  Further, the exposed portion 11a of the semiconductor core 11 is on the lower side of the step portion 11c (the semiconductor layer 12 side is higher), thereby increasing the distance between the outer peripheral surface of the exposed portion 11a of the semiconductor core 11 and the semiconductor layer 12. Therefore, when an n-side electrode is connected to the exposed portion 11a of the semiconductor core 11, a short circuit or leakage current between the n-side electrode and the semiconductor layer 12 can be suppressed.

  The cross sections of the exposed portion 11a and the covering portion 11b of the semiconductor core 11 are not limited to a circular shape, but may be other polygonal cross-sectional shapes such as a hexagon, and the exposed portion and the covering of the semiconductor core. The cross-sectional shape may be different from that of the portion, and the same effect can be obtained if the exposed portion 11a has a smaller diameter than the covered portion 11b of the semiconductor core 11.

  Further, since the cross section orthogonal to the longitudinal direction of the exposed portion 11a of the semiconductor core 11 is substantially circular, the shape of the mask pattern used when the semiconductor core 11 is grown in the manufacturing process may be circular, and the plane direction of the substrate Since the mask layout is not limited by the crystal orientation and the alignment accuracy for aligning the orientation is not required, the manufacturing can be facilitated.

  FIG. 6 is a cross-sectional view of the main part for explaining electrode connection of the exposed portion of the semiconductor core of the bar-shaped light emitting element A. The bar-shaped light emitting element A is arranged so that the longitudinal direction is parallel to the mounting surface. While being mounted on the substrate 10, the exposed portion 11 a of the semiconductor core 11 is connected to the n-side electrode 14 formed on the substrate 10.

  As shown in FIG. 6, in the covered portion 11 b of the semiconductor core 11 covered with the semiconductor layer 12, the outer shape of the exposed portion 11 a of the semiconductor core 11 is smaller than the outer shape of the semiconductor layer 12. Is mounted on the substrate 10 so that the longitudinal direction is parallel to the substrate plane, the contact between the outer peripheral surface of the semiconductor layer 12 and the substrate 10 is facilitated, and the heat dissipation efficiency is improved. That is, the exposed portion 11a of the semiconductor core 11 is deformed because it is thin, and is well connected to the n-side electrode 14, and the covering portion 11b covered with the semiconductor layer 12 of the semiconductor core 11 is in close contact with the substrate 10 without being deformed. Therefore, heat dissipation is excellent. On the other hand, when the outer peripheral surface of the exposed portion 11a of the semiconductor core 11 and the outer peripheral surface of the coating portion 11b covered with the semiconductor layer 12 are coincident, or the outer shape of the exposed portion 11a of the semiconductor core 11 is covered with the semiconductor layer 12 When it is larger than the outer shape of the portion 11b, the exposed portion 11a of the semiconductor core 11 is not easily deformed. Therefore, when the exposed portion 11 a of the semiconductor core 11 is connected to the n-side electrode 14, the covering portion 11 b covered with the semiconductor layer 12 of the semiconductor core 11 is deformed and does not come into close contact with the substrate 10. Gets worse.

  In the first embodiment, the rod-shaped structure light emitting element A in which the semiconductor layer 11 is coated on the rod-shaped semiconductor core 11 having a substantially circular cross section has been described. However, for example, a hexagonal or other polygonal rod-shaped semiconductor core The present invention may be applied to a rod-shaped structure light emitting device that covers a semiconductor layer, a quantum well layer, or the like. The n-type GaN has hexagonal crystal growth, and a substantially hexagonal columnar semiconductor core can be obtained by growing the substrate in the direction perpendicular to the substrate surface in the c-axis direction. Although depending on the growth conditions such as the growth direction and growth temperature, when the diameter of the semiconductor core to be grown is as small as several tens to several hundreds of nanometers, the cross section tends to be almost circular, and the diameter is 0.5 μm. When the thickness is increased from about a few μm, it tends to be easy to grow the cross section in a substantially hexagonal shape.

[Second Embodiment]
FIG. 7 shows a perspective view of a rod-shaped structure light emitting device according to a second embodiment of the present invention.

  As shown in FIG. 7, the rod-shaped structure light emitting element B of the second embodiment does not cover the semiconductor core 21 made of a rod-shaped n-type GaN having a substantially hexagonal cross section and the one end side portion of the semiconductor core 21. And a semiconductor layer 22 made of p-type GaN covering the covering portion 21b of the semiconductor core 21 other than the exposed portion 21a. In the semiconductor core 21, the exposed portion 21a has a smaller diameter than the covering portion 21b, and a step portion 21c is provided between the outer peripheral surface of the exposed portion 21a and the outer peripheral surface of the covering portion 21b. Further, the end surface on the other end side of the semiconductor core 21 is covered with the semiconductor layer 22.

  The rod-shaped structure light emitting element B is manufactured by the same method as the rod-shaped structure light emitting element A of the first embodiment.

  FIG. 8 is a schematic cross-sectional view of the main part of the rod-shaped structure light emitting device of the second embodiment. In FIG. 8, reference numeral 23 denotes an n-side electrode.

  The rod-shaped structure light emitting device B of the second embodiment has the same effect as the rod-shaped structure light emitting device A of the first embodiment.

  According to the rod-shaped structure light emitting element B of the second embodiment, the section perpendicular to the longitudinal direction of the covering portion 21a of the semiconductor core 21 has a hexagonal shape. When mounting so that the longitudinal directions are parallel, it is easy to obtain a contact surface with the substrate at any outer peripheral surface of the semiconductor layer, and the heat dissipation efficiency to the substrate is improved. Therefore, it can suppress that the element temperature at the time of light emission raises, and luminous efficiency falls.

  FIG. 9A is a schematic cross-sectional view of the exposed portion of the semiconductor core of the rod-shaped structure light emitting device A of the first embodiment, and FIG. 9B is a schematic cross-sectional view of the exposed portion of the semiconductor core of the rod-shaped structure light emitting device B of the second embodiment. The figure is shown.

  FIG. 9C is a schematic cross-sectional view of the exposed portion of the semiconductor core of the rod-shaped structure light emitting device of the modification. In the rod-shaped structure light emitting device of this variation, the cross section is orthogonal to the longitudinal direction of the exposed portion 24a of the semiconductor core 24. The cross section is an equilateral triangle.

  Thus, the light extraction efficiency of the cross section perpendicular to the longitudinal direction of the exposed portion of the semiconductor core is more polygonal (for example, a regular hexagon shown in FIG. 9B or a regular triangle shown in FIG. 9C) than the circle shown in FIG. 9A. Can be improved. The reason is that the cross section of the exposed portion of the semiconductor core is more likely to emit light to the outside when the polygon has a smaller number of vertices.

[Third Embodiment]
FIG. 10 is a perspective view of a rod-shaped structure light emitting device according to the third embodiment of the present invention.

  As shown in FIG. 10, the rod-shaped structured light emitting device C of the third embodiment has a semiconductor core 31 made of a rod-shaped n-type GaN and an exposed portion 31 a without covering a portion on one end side of the semiconductor core 31. As described above, a semiconductor layer 32 made of p-type GaN covering the covering portion 31b other than the exposed portion 31a of the semiconductor core 31 is provided. The exposed portion 31a of the semiconductor core 31 has a substantially rectangular cross section perpendicular to the longitudinal direction, and the coated portion 31b of the semiconductor core 31 has a substantially hexagonal cross section perpendicular to the longitudinal direction. A step portion 31c is provided between the outer peripheral surface of the exposed portion 31a of the semiconductor core 31 and the outer peripheral surface of the covering portion 31b. Further, the end surface on the other end side of the semiconductor core 31 is covered with the semiconductor layer 32.

  The rod-shaped structure light emitting device C is manufactured by the same method as the rod-shaped structure light emitting device A of the first embodiment except for the covering portion of the semiconductor core. Here, as to the shape of the exposed portion 31a of the semiconductor core 31, as described above, the diameter and shape of the semiconductor core 31 that grows with the diameter and shape of the growth hole are determined until the height of the growth hole of the mask is exceeded. After the height of the growing semiconductor core 31 exceeds the height of the mask, it is determined by the diameter of the catalytic metal layer that aggregates in an island shape. In the third embodiment, a rectangular growth hole is used.

  The rod-shaped structure light emitting device C of the third embodiment has the same effect as the rod-shaped structure light emitting device A of the first embodiment.

  FIG. 11 is a schematic cross-sectional view of a first modification of the rod-shaped structure light emitting device of the third embodiment. In the first modification, the exposed portion 1031a of the semiconductor core 1031 has a substantially circular cross section perpendicular to the longitudinal direction, and the covered portion 1031b of the semiconductor core 1031 has a substantially hexagonal cross section perpendicular to the longitudinal direction. The cross-sectional shape of the exposed portion 1031a of the semiconductor core 1031 is larger than the cross-sectional shape of the covering portion 1031b. A step portion 1031c is provided between the outer peripheral surface of the exposed portion 1031a of the semiconductor core 1031 and the outer peripheral surface of the covering portion 1031b.

  FIG. 12 is a schematic cross-sectional view of a second modification of the rod-shaped structure light emitting device of the third embodiment. In the second modification, the semiconductor core 1041 has a substantially circular cross section orthogonal to the longitudinal direction of the exposed portion 1041a and a substantially orthogonal cross section orthogonal to the longitudinal direction of the covered portion 1041b. The outer peripheral length of the cross section orthogonal to the longitudinal direction of the exposed portion 1041a of the semiconductor core 1041 is shorter than the outer peripheral length of the cross section orthogonal to the longitudinal direction of the covering portion 1041b of the semiconductor core 1041. That is, the cross-sectional shape of the exposed portion 1031a of the semiconductor core 1031 is smaller than the cross-sectional shape of the covering portion 1031b. A step 1041c is provided between the outer peripheral surface of the exposed portion 1041a of the semiconductor core 1041 and the outer peripheral surface of the covering portion 1041b.

  10 to 12, the cross-sectional shape perpendicular to the longitudinal direction of the exposed portions 31 a, 1031 a, and 1041 a of the semiconductor cores 31, 1031, and 1041, and the semiconductor cores 31, 1031, and 1041 Since the shape of the cross section orthogonal to the longitudinal direction of the covering portions 31b, 1031b, and 1041b of the semiconductor core 31, 1031, 1041b is different from the outer peripheral surface of the semiconductor core 31, 1031, 1041, and the covering portions 31b, 1031b, 1041b. Since the step portions 31c, 1031c, and 1041c are formed at the boundary with the outer peripheral surface, the light extraction efficiency to the outside is improved.

  In addition, the exposed portions 31a, 1031a, 1041a of the semiconductor cores 31, 1031a, 1041 and the semiconductor layers 32, 1032 are compared to the case where the outer peripheral surface of the exposed portion of the semiconductor core is coincident with the outer peripheral surface of the covering portion and there is no step. , 1042, the positions of the end faces of the semiconductor layers 32, 1032, and 1042 are determined by the step portions 31 c, 1031 c, and 1041 c formed at the boundaries between them and the variation in the boundary positions during manufacturing. If the outer peripheral surface of the exposed portion of the semiconductor core is coincident with the outer peripheral surface of the covering portion and there is no step, there may be a gap between the inner wall of the mask growth hole and the semiconductor core during the growth of the semiconductor core. When forming the layer, the semiconductor layer is also formed in the gap region between the inner wall of the growth hole of the mask and the semiconductor core, and the boundary between the exposed portion and the covered portion of the semiconductor core may vary at the position of the upper surface of the mask. However, if there is a step between the outer peripheral surface of the exposed portion of the semiconductor core and the outer peripheral surface of the covering portion, during manufacturing, the semiconductor core is grown with a diameter larger than the inner diameter of the growth hole after exceeding the height of the mask. Even if a gap occurs between the inner wall of the mask growth hole and the semiconductor core, the semiconductor core grows to close the gap, and the semiconductor layer is formed in the gap region between the inner wall of the mask growth hole and the semiconductor core when the semiconductor layer is formed. Which can be prevented.

[Fourth Embodiment]
FIG. 13 shows a cross-sectional view of a rod-shaped structure light emitting device according to a fourth embodiment of the present invention, and FIG. 14 shows a perspective view of the rod-shaped structure light emitting device.

  As shown in FIGS. 13 and 14, the rod-shaped structure light emitting device D of the fourth embodiment includes a semiconductor core 41 made of rod-shaped n-type GaN having a substantially hexagonal cross section, and a portion on one end side of the semiconductor core 41. The semiconductor layer 42 is made of p-type GaN so as to cover the covered portion 41b other than the exposed portion 41a of the semiconductor core 41 so that the exposed portion 41a is not covered. In the semiconductor core 41, the exposed portion 41a has a smaller diameter than the covering portion 41b, and a step portion 41c is provided between the outer peripheral surface of the exposed portion 41a and the outer peripheral surface of the covering portion 41b. The end surface on the other end side of the semiconductor core 41 is covered with the semiconductor layer 42.

  Further, an insulating layer 43 is formed so as to cover the stepped portion 41c of the semiconductor core 41 and the end surface of the semiconductor layer 42 on the stepped portion 41c side, and to cover the stepped portion 41c side of the exposed portion 41a of the semiconductor core 41. is doing. An n-side electrode 44 is connected to the exposed portion 41 a of the semiconductor core 41.

  The rod-shaped structure light emitting device D is manufactured by the same method as the rod-shaped structure light emitting device A of the first embodiment except for the covering portion of the semiconductor core. Here, regarding the formation of the insulating layer 43 covering the step portion 41c of the semiconductor core 41 and the end surface of the semiconductor layer 42 on the step portion 41c side and covering the step portion 41c side of the exposed portion 41a of the semiconductor core 41, In the manufacturing process of the rod-shaped structure light emitting device A according to the first embodiment, instead of removing the region and the mask excluding the portion covering the semiconductor core of the semiconductor layer by lift-off, first, anisotropic dry etching is performed, Of these, the region except the portion covering the semiconductor core and the mask are etched. Then, when the mask is etched halfway, the mask can be partially left as an insulating layer by switching to isotropic dry etching.

When the mask is made of silicon oxide (SiO ₂ ) or silicon nitride (Si ₃ N ₄ ), anisotropic dry etching may be performed using chlorine-based gas such as SiCl ₄ , CF ₄ , CHF ₃ or the like. RIE (Reactive Ion Etching) using a fluorine-based gas can be used. For isotropic dry etching, etching can be performed by using plasma of a gas containing CF _4. . In this embodiment, the length of the insulating layer 43 is determined by the film thickness of the mask removed by dry etching. Further, a gas containing SiCl ₄ is used in anisotropic dry etching, and etching is performed while forming a protective film of a reaction product on the side wall of the mask, so that a semiconductor as shown in FIGS. Processing can be performed in which the outer peripheral surface of the layer 42 and the outer peripheral surface of the insulating layer 43 are substantially matched.

  The rod-shaped structure light emitting device D of the fourth embodiment has the same effect as the rod-shaped structure light emitting device A of the first embodiment.

  Further, in the rod-shaped structure light emitting element D, since the insulating layer 43 can insulate the outer peripheral surface of the exposed portion 41a of the semiconductor core 41 and the semiconductor layer 42, the n-side electrode 44 is connected to the exposed portion 41a of the semiconductor core 41. In this case, the occurrence of a short circuit or leakage current between the n-side electrode 44 and the semiconductor layer 42 can be reliably suppressed.

[Fifth Embodiment]
FIG. 15 shows a cross-sectional view of a bar-shaped structure light emitting element according to a fifth embodiment of the present invention, and FIG. 16 shows a perspective view of the bar-shaped structure light emitting element.

  As shown in FIGS. 15 and 16, the rod-shaped structure light emitting device E of the fifth embodiment includes a semiconductor core 51 made of rod-shaped n-type GaN having a substantially hexagonal cross section, and a portion on one end side of the semiconductor core 51. The semiconductor layer 52 is made of p-type GaN so as to cover the covered portion 51b other than the exposed portion 51a of the semiconductor core 51 so that the exposed portion 51a is not covered.

  The exposed portion 51a of the semiconductor core 51 is connected to the small-diameter portion 51a-1 on the stepped portion 51c side having a smaller diameter than the covering portion 51b and the small-diameter portion 51a-1, and has a larger diameter than the covering portion 51b and the semiconductor layer 52. And a large-diameter portion 51a-2 having the same outer diameter. In the semiconductor core 51, the small-diameter portion 51a-1 of the exposed portion 51a is made smaller in diameter than the covering portion 51b, and a step portion 51c is provided between the outer peripheral surface of the exposed portion 51a and the outer peripheral surface of the covering portion 51b. Further, the end surface on the other end side of the semiconductor core 51 is covered with the semiconductor layer 52.

  The insulating layer 53 covers the stepped portion 51c of the semiconductor core 51 and the end surface of the semiconductor layer 52 on the stepped portion 51c side, and covers the small diameter portion 51a-1 side of the exposed portion 51a of the semiconductor core 51. Is forming. An n-side electrode 54 is connected to the large diameter portion 51a-2 of the exposed portion 51a of the semiconductor core 51.

  The rod-shaped structure light emitting element E is manufactured by the same method as the rod-shaped structure light emitting element A of the first embodiment except for the covering portion of the semiconductor core. In this rod-shaped structure light emitting element E, the small diameter portion 51a-1 on the stepped portion 51c side smaller than the covering portion 51b and the small diameter portion 51a-1 are connected, and have a larger diameter than the covering portion 51b and the same as the semiconductor layer 52. The shape of the exposed portion 51a of the semiconductor core 51 having the outer diameter large portion 51a-2, the stepped portion 51c of the semiconductor core 51 and the end surface of the semiconductor layer 52 on the stepped portion 51c side, and the semiconductor core The insulating layer 53 that covers the small-diameter portion 51a-1 side of the exposed portion 51a of the 51 is a mask and a region excluding the portion of the semiconductor layer that covers the semiconductor core by lift-off in the manufacturing process of the rod-shaped structure light emitting device A of the first embodiment. Instead of the step of removing the film, anisotropic dry etching is performed, and the semiconductor layer is formed by etching the region excluding the portion covering the semiconductor core 51, the mask, and then the substrate. Rukoto can.

  The rod-shaped structure light emitting device E of the fifth embodiment has the same effect as the rod-shaped structure light emitting device A of the first embodiment.

  Further, in the rod-shaped structure light emitting element E, the stepped portion 51c of the semiconductor core 51 and the end surface of the semiconductor layer 52 on the stepped portion 51c side are covered, and the stepped portion 51c side of the exposed portion 51a of the semiconductor core 51 is covered. By providing the insulating layer 53 formed as described above, the insulating layer 53 can insulate the outer peripheral surface of the exposed portion 51a of the semiconductor core 51 and the semiconductor layer 52, so that the n-side electrode is provided on the exposed portion 51a of the semiconductor core 51. When 54 is connected, the occurrence of a short circuit or leakage current between the n-side electrode 54 and the semiconductor layer 52 can be reliably suppressed.

  Furthermore, since the diameter of the large-diameter portion 51a-2 of the exposed portion 51a is larger than the covering portion 51b of the semiconductor core 51, the contact surface with the n-side electrode 54 connected to the exposed portion 51a of the semiconductor core 51 can be increased. The contact resistance can be lowered.

[Sixth Embodiment]
FIG. 17 shows a sectional view of a rod-shaped structure light emitting device according to the sixth embodiment of the present invention.

  As shown in FIG. 17, the rod-shaped structured light emitting element F of the sixth embodiment has a semiconductor core 61 made of a rod-shaped n-type GaN and an exposed portion 61a without covering a portion on one end side of the semiconductor core 61. As described above, the semiconductor layer 62 made of p-type GaN covering the covering portion 61b other than the exposed portion 61a of the semiconductor core 61 and the semiconductor layer 62 are formed so as to cover the semiconductor layer 62 and have a lower electric resistance than the semiconductor layer 62. And a conductive layer 63.

  The exposed portion 61a of the semiconductor core 61 has a substantially circular cross section perpendicular to the longitudinal direction, and the coated portion 61b of the semiconductor core 61 has a substantially hexagonal cross section perpendicular to the longitudinal direction. In the semiconductor core 61, the exposed portion 61a has a smaller diameter than the covering portion 61b, and a step portion 61c is provided between the outer peripheral surface of the exposed portion 61a and the outer peripheral surface of the covering portion 61b. Further, the end surface on the other end side of the semiconductor core 61 is covered with the semiconductor layer 62.

  The conductive layer 63 is made of ITO (tin added indium oxide) having a thickness of 200 nm. The ITO film can be formed by vapor deposition or sputtering. After forming the ITO film, the contact resistance between the semiconductor layer 62 made of p-type GaN and the conductive layer 63 made of ITO can be lowered by performing heat treatment at 500 ° C. to 600 ° C. The conductive layer 63 is not limited to this, and may be, for example, a 5 nm thick Ag / Ni or Au / Ni semitransparent laminated metal film. Vapor deposition or sputtering can be used to form this laminated metal film. Furthermore, in order to further reduce the resistance of the conductive layer, a laminated metal film of Ag / Ni or Au / Ni may be laminated on the ITO film.

  The rod-shaped structure light emitting element F is manufactured by the same method as the rod-shaped structure light emitting element A of the first embodiment. In this rod-shaped structure light emitting element F, after removing the catalytic metal layer, a semiconductor layer 62 covering the semiconductor core 61 is formed, and further, an ITO film is formed as a conductive layer so as to cover the semiconductor layer 62, and then an anisotropic dry layer is formed. Etching removes the region of the ITO film excluding the portion covering the semiconductor layer 62, and then removing the region excluding the portion of the semiconductor layer covering the semiconductor core 61 and the mask by lift-off, as in the first embodiment. Can be formed.

  Further, the rod-like structure light emitting element F of the sixth embodiment has the same effect as the rod-like structure light emitting element A of the first embodiment.

  According to the rod-shaped structure light emitting element F of the sixth embodiment, the section perpendicular to the longitudinal direction of the covering portion 61a of the semiconductor core 61 has a hexagonal shape. When mounting so that the longitudinal directions are parallel, it is easy to obtain a contact surface with the substrate at any outer peripheral surface of the semiconductor layer, and the heat dissipation efficiency to the substrate is improved. Therefore, it can suppress that the element temperature at the time of light emission raises, and luminous efficiency falls.

  Further, the exposed portion 61a of the semiconductor core 61 is different from the shape of the cross section orthogonal to the longitudinal direction of the exposed portion 61a of the semiconductor core 61 and the shape of the cross section orthogonal to the longitudinal direction of the covered portion 61b of the semiconductor core 61. Since the step portion 61c is formed at the boundary between the outer peripheral surface of the cover and the outer peripheral surface of the covering portion 61b, the light extraction efficiency to the outside is improved.

  In addition, by connecting the semiconductor layer 62 to the p-side electrode through the conductive layer 63 made of a material having a lower electrical resistance than the semiconductor layer 62, current does not concentrate on the electrode connection portion and is not biased. By forming a path, the entire side surface of the semiconductor core 61 can be efficiently emitted, and the light emission efficiency is further improved.

[Seventh Embodiment]
FIG. 18 is a sectional view of a rod-shaped structure light emitting device according to the seventh embodiment of the present invention.

  As shown in FIG. 18, the rod-shaped structured light emitting element G of the seventh embodiment has a semiconductor core 71 made of a rod-shaped n-type GaN and an exposed portion 71a without covering a portion on one end side of the semiconductor core 71. As described above, the quantum well layer 72 made of p-type InGaN covering the portion other than the exposed portion 71 a of the semiconductor core 71, the semiconductor layer 73 made of p-type GaN covering the outer peripheral surface of the quantum well layer 72, and the semiconductor layer 73 And a conductive layer 74 made of a material having an electric resistance lower than that of the semiconductor layer 73.

  The exposed portion 71a of the semiconductor core 71 has a substantially circular cross section perpendicular to the longitudinal direction, and the coated portion 71b of the semiconductor core 71 has a substantially hexagonal cross section perpendicular to the longitudinal direction. In the semiconductor core 71, the exposed portion 71a has a smaller diameter than the covering portion 71b, and a step portion 71c is provided between the outer peripheral surface of the exposed portion 71a and the outer peripheral surface of the covering portion 71b. Further, the end surface on the other end side of the semiconductor core 71 is covered with a semiconductor layer 72.

  The conductive layer 74 is formed of ITO (tin-added indium oxide) having a thickness of 200 nm. The ITO film can be formed by vapor deposition or sputtering. After forming the ITO film, the contact resistance between the semiconductor layer 72 made of p-type GaN and the conductive layer 74 made of ITO can be lowered by performing heat treatment at 500 ° C. to 600 ° C. The conductive layer 74 is not limited to this, and may be, for example, a 5 nm thick Ag / Ni or Au / Ni semi-transparent laminated metal film. Vapor deposition or sputtering can be used to form this laminated metal film. Furthermore, in order to further reduce the resistance of the conductive layer, a laminated metal film of Ag / Ni or Au / Ni may be laminated on the ITO film.

  The rod-shaped structure light emitting element G is manufactured by the same method as the rod-shaped structure light emitting element A of the first embodiment. In this rod-shaped structure light emitting element G, a quantum well layer 72 and a semiconductor layer 73 covering the semiconductor core 71 are formed after the removal of the catalytic metal layer, and an ITO film is formed as a conductive layer so as to cover the semiconductor layer 73 of the ITO film. Next, after removing the region excluding the portion covering the semiconductor layer 72 by anisotropic dry etching, the portion covering the semiconductor core in the quantum well layer and the semiconductor layer is removed by lift-off as in the first embodiment. It can be formed by removing the region and the mask.

  Moreover, the rod-shaped structure light emitting element G of the seventh embodiment has the same effect as the rod-shaped structure light emitting element A of the first embodiment.

  According to the rod-shaped structure light emitting element G of the seventh embodiment, the section perpendicular to the longitudinal direction of the covering portion 71a of the semiconductor core 71 has a hexagonal shape. When mounting so that the longitudinal directions are parallel, it is easy to obtain a contact surface with the substrate at any outer peripheral surface of the semiconductor layer, and the heat dissipation efficiency to the substrate is improved. Therefore, it can suppress that the element temperature at the time of light emission raises, and luminous efficiency falls.

  Further, the exposed portion 71a of the semiconductor core 71 is different from the shape of the cross section orthogonal to the longitudinal direction of the exposed portion 71a of the semiconductor core 71 and the shape of the cross section orthogonal to the longitudinal direction of the covered portion 71b of the semiconductor core 71. Since the stepped portion 71c is formed at the boundary between the outer peripheral surface of the cover and the outer peripheral surface of the covering portion 71b, the light extraction efficiency to the outside is improved.

  Further, by connecting the semiconductor layer 73 to the p-side electrode through the conductive layer 74 made of a material having a lower electric resistance than the semiconductor layer 73, current is not concentrated and biased in the electrode connection portion, and a wide current By forming a path, the entire side surface of the semiconductor core 71 can be efficiently emitted, and the light emission efficiency is further improved.

  Further, by forming the quantum well layer 72 between the outer peripheral surface of the covering portion 71 b of the semiconductor core 71 and the semiconductor layer 73, the light emission efficiency can be improved by the quantum confinement effect of the quantum well layer 72.

  The quantum well layer may have a multiple quantum well structure in which GaN barrier layers and InGaN quantum well layers are alternately stacked.

[Eighth Embodiment]
FIG. 19 shows a sectional view of a rod-shaped structure light emitting device according to an eighth embodiment of the present invention. The rod-shaped structure light emitting device of the eighth embodiment has the same configuration as the rod-shaped structure light emitting device of the seventh embodiment except for the cap layer.

  As shown in FIG. 19, the rod-shaped structure light emitting element H of the eighth embodiment includes a semiconductor core 81 made of a rod-shaped n-type GaN having a substantially hexagonal cross section, and a cap layer that covers one end face of the semiconductor core 81. 82 and the outer peripheral surface of the covering portion 81b other than the exposed portion 81a of the semiconductor core 81 so that the exposed portion 81a is formed without covering the portion opposite to the portion of the semiconductor core 81 covered with the cap layer 82. A quantum well layer 83 made of p-type InGaN, a semiconductor layer 84 made of p-type GaN covering the outer peripheral surface of the quantum well layer 83, and a conductive layer 85 covering the outer peripheral surface of the semiconductor layer 84 are provided.

  In the semiconductor core 81, the exposed portion 81a has a smaller diameter than the covering portion 81b, and a step portion 81c is provided between the outer peripheral surface of the exposed portion 81a and the outer peripheral surface of the covering portion 81b. The outer peripheral surface of the semiconductor core 81 and the outer peripheral surface of the cap layer 82 are covered with a continuous quantum well layer 83 and a semiconductor layer 84.

  The conductive layer 85 is formed of ITO (tin-added indium oxide) having a thickness of 200 nm. The ITO film can be formed by vapor deposition or sputtering. After forming the ITO film, the contact resistance between the semiconductor layer 84 made of p-type GaN and the conductive layer 85 made of ITO can be lowered by performing heat treatment at 500 to 600 ° C. The conductive layer 85 is not limited to this, and may be, for example, a 5 nm thick Ag / Ni or Au / Ni semi-transparent laminated metal film. Vapor deposition or sputtering can be used to form this laminated metal film. Furthermore, in order to further reduce the resistance of the conductive layer, a laminated metal film of Ag / Ni or Au / Ni may be laminated on the ITO film.

  FIG. 20 is a schematic cross-sectional view of the main part of the rod-shaped structure light emitting element H. As shown in FIG. 20, the rod-shaped structure light emitting element H of the eighth embodiment has a larger electric resistance than the semiconductor layer 84. The cap layer 82 made of a material covers one end surface of the semiconductor core 81, so that a current flows between the p-side electrode 86 connected to the cap layer 82 side of the semiconductor core 81 and the semiconductor core 81 via the cap layer 82. On the other hand, current flows between the p-side electrode 86 and the outer peripheral surface side of the semiconductor core 81 through the conductive layer 85 and the semiconductor layer 84 having lower resistance than the cap layer 82. As a result, current concentration on the end surface of the semiconductor core 81 on the side where the cap layer 82 is provided is suppressed, and light is not concentrated on the end surface of the semiconductor core 81, so that light from the side surface of the semiconductor core 81 can be reduced. Extraction efficiency is improved.

  The rod-shaped structure light emitting element H of the eighth embodiment has the same effect as the rod-shaped structure light emitting element of the seventh embodiment.

  In the rod-shaped structure light emitting element, when an n-side electrode (not shown) is connected to the exposed portion 81a of the semiconductor core 81, and the p-side electrode 86 is connected to the side of the semiconductor core 81 where the cap layer 82 is provided. Since one end face of the semiconductor core 81 is not exposed by the cap layer 82, the semiconductor core 81 and the p-side electrode 86 can be easily electrically connected via the semiconductor layer 84 and the conductive layer 85 at the end. . As a result, the area blocked by the p-side electrode 86 in the entire side surface of the semiconductor core 81 covered with the semiconductor layer 84 and the conductive layer 85 can be minimized, and the light extraction efficiency can be improved. Further, the current concentration on the end surface of the semiconductor core 81 on the side where the cap layer 82 is provided is suppressed, and the light extraction efficiency from the side surface of the semiconductor core 81 is reduced without concentration of light emission on the end surface of the semiconductor core. Will improve.

  Note that, at the end of the semiconductor core 81 on the cap layer 82 side, only the conductive layer 85 and the p-side electrode 86 may be electrically connected without being connected to the cap layer 82.

[Ninth Embodiment]
FIG. 21 is a perspective view of a light-emitting device provided with the rod-shaped structure light-emitting element according to the ninth embodiment of the present invention.

  In the light emitting device according to the ninth embodiment, as shown in FIG. 21, an insulating substrate 90 having metal electrodes 98 and 99 formed on the mounting surface, and a longitudinal direction of the insulating substrate 90 on the insulating substrate 90. And a rod-shaped structure light emitting element I mounted so as to be parallel to the mounting surface.

  The rod-shaped structure light emitting element I includes a semiconductor core 91 made of a rod-shaped n-type GaN and an exposed portion 91a other than the exposed portion 91a of the semiconductor core 91 so as not to cover a portion on one end side of the semiconductor core 91. And a semiconductor layer 92 made of p-type GaN covering the covering portion 91b.

  The exposed portion 91a of the semiconductor core 91 has a substantially circular cross section perpendicular to the longitudinal direction, and the covering portion 91b of the semiconductor core 91 has a substantially hexagonal cross section perpendicular to the longitudinal direction. The exposed portion 91a of the semiconductor core 91 has a smaller diameter than the covering portion 91b, and a step portion 91c is provided between the outer peripheral surface of the exposed portion 91a and the outer peripheral surface of the covering portion 91b.

  As shown in FIG. 21, the exposed portion 91 a on one end side of the rod-shaped structure light emitting element I is connected to the metal electrode 98, and the semiconductor layer 92 on the other end side of the rod-shaped structure light emitting element I is connected to the metal electrode 99. .

  Here, the rod-shaped structure light emitting device I is used when the droplets in the gap between the substrate surface and the rod-shaped structure light emitting device are reduced by evaporation when the IPA aqueous solution is dried in the method for arranging the rod-shaped structure light emitting devices of the twelfth embodiment described later. The central portion is bent by the generated stiction and is in contact with the insulating substrate 90.

  According to the light emitting device of the ninth embodiment, the rod-shaped structure light-emitting element I mounted on the insulating substrate 90 so that the longitudinal direction is parallel to the mounting surface includes the outer peripheral surface of the semiconductor layer 92 and the insulating substrate 90. Since the mounting surface comes into contact, the heat generated in the rod-shaped structure light emitting element I can be efficiently radiated from the semiconductor layer 92 to the insulating substrate 90. Therefore, a light emitting device with high luminous efficiency and good heat dissipation can be realized. Note that, in the rod-shaped structure light-emitting element in which the conductive layer is formed so as to cover the semiconductor layer, the same effect can be obtained by bringing the outer peripheral surface of the conductive layer into contact with the mounting surface of the insulating substrate.

  Further, in the above light emitting device, since the rod-shaped structure light emitting element I is disposed on the insulating substrate 90 in a horizontal direction, the thickness including the insulating substrate 90 can be reduced. In the above light emitting device, for example, a micro-order size having a diameter of 1 μm and a length of 10 μm, or a fine rod-shaped light-emitting element I having a nano-order size of at least a diameter or length of less than 1 μm is used. The amount of semiconductor can be reduced, and a backlight, a lighting device, a display device, and the like that can be reduced in thickness and weight can be realized by using the light emitting device.

  In the ninth embodiment, any of the rod-shaped structure light emitting elements of the first to ninth embodiments may be used as the rod-shaped structure light emitting element.

[Tenth embodiment]
FIG. 22 shows a side view of a light-emitting device provided with a rod-like structure light-emitting element according to the tenth embodiment of the present invention.

  As shown in FIG. 22, the light emitting device of the tenth embodiment includes an insulating substrate 100 and a rod-like structure mounted on the insulating substrate 100 so that the longitudinal direction is parallel to the mounting surface of the insulating substrate 100. And a light emitting element J.

  The rod-shaped structure light emitting element J includes a semiconductor core 101 made of rod-shaped n-type GaN, a cap layer 102 (shown in FIG. 23) covering one end surface of the semiconductor core 51, and a semiconductor covered with the cap layer 102. A quantum well layer 103 made of p-type InGaN covering the outer peripheral surface of the covering portion 101b other than the exposed portion 101a of the semiconductor core 101 so as to make the exposed portion 101a without covering the portion opposite to the portion of the core 101; A semiconductor layer 104 made of p-type GaN covering the outer peripheral surface of the quantum well layer 103 and a conductive layer 105 covering the outer peripheral surface of the semiconductor layer 104 are provided.

  The exposed portion 101a of the semiconductor core 101 has a substantially circular cross section perpendicular to the longitudinal direction, and the coated portion 101b of the semiconductor core 101 has a substantially hexagonal cross section perpendicular to the longitudinal direction. The exposed portion 101a of the semiconductor core 101 has a smaller diameter than the covering portion 101b, and a step portion 101c is provided between the outer peripheral surface of the exposed portion 101a and the outer peripheral surface of the covering portion 101b.

  A metal layer 106 as an example of a second conductive layer is formed on the conductive layer 105 and on the insulating substrate 100 side. The metal layer 106 covers the lower half of the outer peripheral surface of the conductive layer 105. The conductive layer 105 is made of ITO. The conductive layer is not limited to this, and may be, for example, a 5 nm thick Ag / Ni or Au / Ni semi-transparent laminated metal film. Vapor deposition or sputtering can be used to form this laminated metal film. Furthermore, in order to further reduce the resistance of the conductive layer, a laminated metal film of Ag / Ni or Au / Ni may be laminated on the ITO film. The metal layer 106 is not limited to Al, and Cu, W, Ag, Au, or the like may be used.

  As shown in FIG. 23, the light emitting device of the tenth embodiment includes an insulating substrate 100 having metal electrodes 107 and 108 formed on the mounting surface, and a longitudinal direction of the insulating substrate 100 on the insulating substrate 100. And a rod-shaped structure light emitting element J mounted so as to be parallel to the mounting surface.

  The exposed portion 101a on one end side of the rod-shaped structure light emitting element J is connected to the metal electrode 107 by an adhesive portion 109A such as a conductive adhesive, and the metal layer 106 on the other end side of the rod-shaped structure light emitting element J is connected to the metal electrode 108. They are connected by an adhesive portion 109B such as a conductive adhesive.

  Here, the rod-like structure light emitting element J is used when the droplets in the gap between the substrate surface and the rod-like structure light emitting element are reduced by evaporation when the IPA aqueous solution is dried in the method for arranging the rod-like structure light emitting elements of the twelfth embodiment described later. The central portion is bent by the generated stiction and is in contact with the insulating substrate 100.

  According to the light emitting device of the tenth embodiment, as an example of the second conductive layer made of a material having lower electrical resistance than the semiconductor layer 104 on the conductive layer 105 of the rod-shaped structure light emitting element J and on the insulating substrate 100 side. By forming the metal layer 106, the conductive layer 105 covering the outer peripheral surface of the semiconductor core 101 is provided on the side opposite to the insulating substrate 100 of the rod-shaped structure light emitting element J without the metal layer 106. The resistance can be reduced by the metal layer 106 without sacrificing the ease of current flow through the entire semiconductor layer 104. In addition, the conductive layer 105 covering the outer peripheral surface of the semiconductor core 101 cannot use a low-resistance material because a material with low transmittance cannot be used in consideration of light emission efficiency, but the metal layer 106 has a transmittance. It is possible to use a conductive material that prioritizes low resistance. Furthermore, the rod-shaped structure light emitting element J mounted on the insulating substrate 100 so that the longitudinal direction is parallel to the mounting surface is generated in the rod-shaped structure light emitting element J because the metal layer 106 is in contact with the mounting surface of the insulating substrate 100. Thus, the heat can be efficiently radiated to the insulating substrate 100 through the metal layer 106.

[Eleventh embodiment]
FIG. 24 is a perspective view of the light emitting device according to the eleventh embodiment of the present invention. In the eleventh embodiment, a rod-shaped structure light emitting device having the same configuration as that of the rod-shaped structure light emitting device B of the second embodiment is used. In addition, you may use any of the said rod-shaped structure light emitting element of the said 1st, 3rd-10th embodiment for a rod-shaped structure light emitting element.

  As shown in FIG. 24, the light emitting device of the eleventh embodiment includes an insulating substrate 200 in which metal electrodes 201 and 202 are formed on the mounting surface, and a longitudinal direction of the insulating substrate 200 on the insulating substrate 200. And a rod-shaped structure light emitting element K mounted so as to be parallel to the mounting surface. A third metal electrode 203 as an example of a metal portion is formed on the insulating substrate 200 between the metal electrodes 201 and 202 on the insulating substrate 200 and below the rod-shaped structure light emitting element K. In FIG. 24, only a part of the metal electrodes 201, 202, 203 is shown.

  The rod-shaped structure light emitting element K has a semiconductor core 111 made of a rod-shaped n-type GaN having a substantially hexagonal cross section, and an exposed portion 111a without covering a portion opposite to the portion of the semiconductor core 111. And a semiconductor layer 112 made of p-type GaN covering the outer peripheral surface of the covering portion 111b other than the exposed portion 111a of the semiconductor core 111. In the semiconductor core 111, the exposed portion 111a has a smaller diameter than the covering portion 111b, and a step portion 111c is provided between the outer peripheral surface of the exposed portion 111a and the outer peripheral surface of the covering portion 111b. Further, the end surface on the other end side of the semiconductor core 111 is covered with the semiconductor layer 112.

  According to the light emitting device of the eleventh embodiment, the metal electrode 203 is formed between the electrodes 201 and 202 on the insulating substrate 200 and below the rod-shaped structure light emitting element K, so that both ends become the metal electrodes 201 and 202. Since the center side of the connected rod-shaped structure light emitting element K is supported by being brought into contact with the surface of the metal electrode 203, the both-end supported rod-shaped structure light emitting element K is supported by the metal electrode 203 without being bent, and the rod-shaped structure light emitting element is supported. Heat generated in the element K can be efficiently radiated from the semiconductor layer 112 to the insulating substrate 200 through the metal electrode 203.

  As shown in FIG. 25, each of the metal electrode 201 and the metal electrode 202 includes a base portion 201a, 202a that is substantially parallel to each other at a predetermined interval, and a position between the base portion 201a, 202a from a position where the base portions 201a, 202a face each other. It has a plurality of electrode portions 201b and 202b extending. One rod-shaped structure light emitting element K is arranged in the electrode part 201b of the metal electrode 201 and the electrode part 202b of the metal electrode 202 opposite to the electrode part 201b. A butterfly-shaped third metal electrode 203 having a narrow central portion is formed on the insulating substrate 200 between the electrode portion 201b of the metal electrode 201 and the electrode portion 202b of the metal electrode 202 opposed thereto.

  The third metal electrodes 203 adjacent to each other are electrically separated from each other. As shown in FIG. 25, even if the directions of the rod-shaped structure light emitting elements K adjacent to each other are reversed, the third metal electrodes 203 are interposed via the metal electrodes 203. Thus, the metal electrode 201 and the metal electrode 202 can be prevented from being short-circuited.

[Twelfth embodiment]
Next, a light emitting device, a backlight, an illuminating device, and a display device each including a bar-shaped structured light emitting element according to a twelfth embodiment of the present invention will be described. In the twelfth embodiment, the rod-shaped structure light emitting elements of the first to tenth embodiments are arranged on an insulating substrate. The arrangement of the rod-shaped structure light-emitting elements is the same as that disclosed in Japanese Patent Application No. 2007-102848 (Japanese Patent Application Laid-Open No. 2008-260073), “Microstructure Arrangement Method, Substrate Arranged with Fine Structure, and Integrated Circuit Device” And display device ".

  FIG. 26 shows a plan view of an insulating substrate used in the light emitting device, backlight, illumination device and display device of the twelfth embodiment. As shown in FIG. 26, metal electrodes 301 and 302 are formed on the surface of the insulating substrate 300. The insulating substrate 300 is an insulating material such as glass, ceramic, aluminum oxide, resin, or a substrate in which a silicon oxide film is formed on a semiconductor surface such as silicon, and the surface is insulative. When a glass substrate is used, it is desirable to form a base insulating film such as a silicon oxide film or a silicon nitride film on the surface.

  The metal electrodes 301 and 302 are formed in a desired electrode shape using a printing technique. The metal film and the photosensitive film may be uniformly laminated, and a desired electrode pattern may be exposed and etched.

  Although omitted in FIG. 26, pads are formed on the metal electrodes 301 and 302 so that potentials can be applied from the outside. A rod-shaped structure light emitting element is arranged in a portion (arrangement region) where the metal electrodes 301 and 302 face each other. In FIG. 26, 2 × 2 arrangement regions for arranging rod-shaped structure light emitting elements are arranged, but any number may be arranged.

  FIG. 27 is a schematic sectional view taken along line XXVII-XXVII in FIG.

  First, as shown in FIG. 27, isopropyl alcohol (IPA) 311 including a rod-shaped structure light emitting element 310 is thinly applied on an insulating substrate 300. In addition to IPA 311, ethylene glycol, propylene glycol, methanol, ethanol, acetone, or a mixture thereof may be used. Alternatively, the IPA 311 can use a liquid made of another organic material, water, or the like.

  However, if a large current flows between the metal electrodes 301 and 302 through the liquid, a desired voltage difference cannot be applied between the metal electrodes 301 and 302. In such a case, the entire surface of the insulating substrate 300 may be coated with an insulating film of about 10 nm to 30 nm so as to cover the metal electrodes 301 and 302.

The thickness of applying the IPA 311 including the rod-shaped structure light emitting element 310 is such that the rod-shaped structure light emitting element 310 can move in the liquid so that the rod-shaped structure light emitting element 310 can be arranged in the next step of arranging the rod-shaped structure light emitting element 310. That's it. Therefore, the thickness of applying the IPA 311 is equal to or greater than the thickness of the rod-shaped structure light emitting element 310, and is, for example, several μm to several mm. If the applied thickness is too thin, the rod-like structure light emitting element 310 is difficult to move. If it is too thick, the time for drying the liquid becomes long. Further, the amount of the rod-like structure light emitting element 310 is preferably 1 × 10 ⁴ pieces / cm ³ to 1 × 10 ⁷ pieces / cm ³ with respect to the amount of IPA.

  In order to apply the IPA 311 including the rod-shaped structure light-emitting element 310, a frame is formed around the outer periphery of the metal electrode on which the rod-shaped structure light-emitting element 310 is arranged, and the IPA 311 including the rod-shaped structure light-emitting element 310 is formed in a desired thickness. It may be filled so that However, when the IPA 311 including the rod-shaped structure light emitting element 310 has viscosity, it can be applied to a desired thickness without requiring a frame.

  A liquid made of IPA, ethylene glycol, propylene glycol,..., Or a mixture thereof, or other organic substances, or a liquid such as water is desirable for the arrangement process of the rod-shaped structure light emitting element 310 to have a low viscosity, It is desirable that it evaporates easily when heated.

  Next, a potential difference is applied between the metal electrodes 301 and 302. In the twelfth embodiment, a potential difference of 1V was appropriate. The potential difference between the metal electrodes 301 and 302 can be 0.1 to 10 V, but if the voltage is 0.1 V or less, the arrangement of the rod-shaped structure light emitting elements 310 is poor, and if it is 10 V or more, insulation between the metal electrodes becomes a problem. start. Therefore, it is preferably 1 to 5V, and more preferably about 1V.

  FIG. 28 shows the principle that the rod-shaped structure light emitting elements 310 are arranged on the metal electrodes 301 and 302. As shown in FIG. 28, when a potential VL is applied to the metal electrode 301 and a potential VR (VL <VR) is applied to the metal electrode 302, a negative charge is induced in the metal electrode 301 and a positive charge is applied to the metal electrode 302. Is induced. When the rod-shaped structure light emitting element 310 approaches, a positive charge is induced on the side close to the metal electrode 301 and a negative charge is induced on the side close to the metal electrode 302. The charge is induced in the rod-shaped structure light emitting element 310 by electrostatic induction. That is, the rod-shaped structure light emitting element 310 placed in the electric field is caused by the charge being induced on the surface until the internal electric field becomes zero. As a result, an attractive force is exerted between each electrode and the rod-shaped structure light emitting element 310 by an electrostatic force, and the rod-shaped structure light emitting element 310 follows the electric lines of force generated between the metal electrodes 301 and 302 and each rod-shaped structure light emitting element 310. Since the charges induced in the are substantially equal, the repulsive force caused by the charges causes the charges to be regularly arranged in a fixed direction at almost equal intervals. However, for example, in the rod-shaped structure light-emitting element shown in FIG. 1 of the first embodiment, the direction of the exposed portion 11a side of the semiconductor core 11 covered with the semiconductor layer 12 is not constant, but is random (another embodiment). The same applies to the rod-shaped structure light-emitting element.

  As described above, an electric field generated between the metal electrodes 301 and 302 in the rod-shaped structure light emitting element 310 generates charges in the rod-shaped structure light emitting element 310, and the rod-shaped structure light emitting elements 310 are applied to the metal electrodes 301 and 302 by the attractive force of the charges. Therefore, the size of the rod-like structure light emitting element 310 needs to be a size that can move in the liquid. Therefore, the size of the rod-shaped structure light emitting element 310 varies depending on the application amount (thickness) of the liquid. When the amount of liquid applied is small, the rod-shaped structure light emitting element 310 must be nano-order size, but when the amount of liquid applied is large, it may be micro-order size.

  When the rod-shaped structure light-emitting element 310 is not electrically neutral and is charged positively or negatively, the rod-shaped structure light-emitting element 310 can be formed only by giving a static potential difference (DC) between the metal electrodes 301 and 302. It cannot be arranged stably. For example, when the rod-shaped structure light emitting element 310 is positively charged as a net, the attractive force with the metal electrode 302 in which the positive charge is induced becomes relatively weak. Therefore, the arrangement of the rod-shaped structure light emitting elements 310 is not targeted.

  In such a case, it is preferable to apply an AC voltage between the metal electrodes 301 and 302 as shown in FIG. In FIG. 29, a reference potential is applied to the metal electrode 302 and an AC voltage having an amplitude VPPL / 2 is applied to the metal electrode 301. By doing so, even when the rod-shaped structure light emitting element 310 is charged, the arrangement can be kept as a target. In this case, the frequency of the AC voltage applied to the metal electrode 302 is preferably 10 Hz to 1 MHz, and more preferably 50 Hz to 1 kHz because the arrangement is most stable. Furthermore, the AC voltage applied between the metal electrodes 301 and 302 is not limited to a sine wave, but may be any voltage that varies periodically, such as a rectangular wave, a triangular wave, and a sawtooth wave. VPPL was preferably about 1V.

  Next, after the rod-shaped structure light emitting elements 310 are arranged on the metal electrodes 301 and 302, the insulating substrate 300 is heated to evaporate the liquid and dry the metal. The wires are arranged at equal intervals along the lines of electric force between 302 and fixed.

  FIG. 30 is a plan view of the insulating substrate 300 on which the rod-shaped structure light emitting elements 310 are arranged. By using the insulating substrate 300 on which the rod-shaped structure light emitting elements 310 are arranged for a backlight of a liquid crystal display device or the like, it is possible to realize a backlight that can be reduced in thickness and weight, has high luminous efficiency, and saves power. it can. Further, by using the insulating substrate 300 in which the rod-shaped structure light emitting elements 310 are arranged as a lighting device, it is possible to realize a lighting device that can be reduced in thickness and weight, has high luminous efficiency, and saves power.

  FIG. 31 is a plan view of a display device using an insulating substrate on which the rod-shaped structure light emitting elements 310 are arranged. As illustrated in FIG. 31, the display device 400 includes a display portion 401, a logic circuit portion 402, a logic circuit portion 403, a logic circuit portion 404, and a logic circuit portion 405 on an insulating substrate 410. In the display portion 401, rod-shaped structure light emitting elements 310 are arranged in pixels arranged in a matrix.

  FIG. 32 is a circuit diagram of a main part of the display unit 401 of the display device 400. As shown in FIG. 32, the display unit 401 of the display device 400 has a plurality of scanning signal lines GL (see FIG. 32, only one line is shown) and a plurality of data signal lines SL (only one line is shown in FIG. 32), and two adjacent scanning signal lines GL and two adjacent data signal lines SL are provided. Pixels are arranged in a matrix in a portion surrounded by. This pixel has a switching element Q1 having a gate connected to the scanning signal line GL and a source connected to the data signal line SL, a switching element Q2 having a gate connected to the drain of the switching element Q1, and the switching element Q2. And a plurality of light emitting diodes D1 to Dn (bar-shaped structure light emitting element 310) driven by the switching element Q2.

  The pn polarities of the rod-shaped structure light emitting elements 310 are not aligned on one side, but are randomly arranged. For this reason, at the time of driving, it is driven by an alternating voltage, and the bar-shaped structure light emitting elements 310 having different polarities emit light alternately.

  Further, according to the display device, by using the rod-shaped structure light emitting element, it is possible to realize a display device that can be reduced in thickness and weight, has high luminous efficiency, and saves power.

  In addition, according to the method for manufacturing the light emitting device, the backlight, the lighting device, and the display device, the insulating substrate 300 in which the array region is formed in units of two metal electrodes 301 and 302 to which independent potentials are respectively applied. The liquid containing the rod-shaped structure light emitting element 310 of nano order size or micro order size is applied on the insulating substrate 300. Thereafter, independent voltages are applied to the two metal electrodes 301 and 302, respectively, so that the fine rod-shaped light emitting elements 310 are arranged at positions defined by the two metal electrodes 301 and 302. Thereby, the rod-shaped structure light emitting element 310 can be easily arranged on the predetermined insulating substrate 300.

  Moreover, in the manufacturing method of the light emitting device, the backlight, the lighting device, and the display device, the light emitting device, the backlight, the lighting device, and the display device that can reduce the amount of semiconductors used and can be reduced in thickness and weight are manufactured. can do. In addition, the light emitting element 310 has a light emitting region that is widened by emitting light from the entire side surface of the semiconductor core covered with the semiconductor layer, so that the light emitting device, backlight, and illumination with high luminous efficiency and power saving can be obtained. A device and a display device can be realized.

  In the first to twelfth embodiments, the semiconductor core, the cap layer, and the semiconductor layer are made of a semiconductor having GaN as a base material. The present invention may be applied to a light-emitting element using a semiconductor whose base material is. Further, although the semiconductor core is n-type and the semiconductor layer is p-type, the present invention may be applied to a rod-shaped structure light-emitting element having a reverse conductivity type. Moreover, although the rod-shaped structure light emitting element having a circular or hexagonal rod-shaped semiconductor core has been described, the present invention is not limited to this, and the rod-like structure may be an ellipse-like rod shape, or a rod shape having another polygonal shape such as a triangle. The present invention may be applied to a rod-shaped structure light emitting device having a semiconductor core.

  In the first to twelfth embodiments, the rod-shaped structure light emitting element has a diameter of 1 μm and a length of 10 μm to 30 μm. However, at least one of the diameters or lengths is less than 1 μm in the nano order. A size element may be used. The diameter of the semiconductor core of the rod-shaped structure light emitting element is preferably 500 nm or more and 100 μm or less, and variation in the diameter of the semiconductor core can be suppressed as compared with the rod-shaped structure light emitting element of several tens nm to several hundred nm, and the light emission area, that is, the light emission characteristics. Variation can be reduced and yield can be improved.

  In the first to twelfth embodiments, the semiconductor core and the cap layer are grown using the MOCVD apparatus. However, the semiconductor core and the cap layer are grown using another crystal growth apparatus such as an MBE (molecular beam epitaxial) apparatus. A cap layer may be formed. Further, although the semiconductor core is crystal-grown on the substrate using a mask having a growth hole, the semiconductor core may be crystal-grown from the metal seed by arranging a metal species on the substrate.

  In the twelfth embodiment, the rod-shaped structure light emitting element 300 is arranged between the metal electrodes 301 and 302 by applying a potential difference to the two metal electrodes 301 and 302 formed on the surface of the insulating substrate 300. Not limited to this, a third electrode is formed between two electrodes formed on the surface of the insulating substrate, and an independent voltage is applied to each of the three electrodes. You may arrange in the position.

  Although specific embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

11, 21, 24, 31, 41, 51, 61, 71, 81, 91, 101, 111 ... Semiconductor core 11a, 21a, 24a, 31a, 41a, 51a, 61a, 71a, 81a, 91a, 101a, 111a ... Exposed portion 11b, 21b, 31b, 41b, 51b, 61b, 71b, 81b, 91b, 101b, 111b ... Covered portion 11c, 21c, 31c, 41c, 51c, 61c, 71c, 81c, 91c, 101c, 111c ... Stepped portion 12, 22, 32, 42, 52, 62, 73, 84, 92, 104, 112 ... Semiconductor layer 23, 44, 54 ... n-side electrode 43, 53 ... Insulating layer 63, 74, 85, 105 ... Conductive layer 72 , 103 ... Quantum well layer 82,102 ... Cap layer 90,100,200 ... Insulating substrate 98,99,107,108,201,202,203 ... Metal electrode 106 ... Metal layer 300 ... Insulating substrate 301,302 ... Metal electrode 310 ... Bar-shaped structure light emitting element 311 ... IPA
DESCRIPTION OF SYMBOLS 400 ... Display apparatus 401 ... Display part 402,403,404,405 ... Logic circuit part 410 ... Insulating board AK ... Bar-shaped structure light emitting element

Claims (18)

A rod-shaped first conductive type semiconductor core;
A second-conductivity-type semiconductor layer covering a portion other than the exposed portion of the semiconductor core so as not to cover a portion on one end side of the semiconductor core;
With
Providing a step between the outer peripheral surface of the exposed portion of the semiconductor core that is not covered by the semiconductor layer and the outer peripheral surface of the covering portion of the semiconductor core that is covered by the semiconductor layer;
A rod-shaped structure light emitting element, wherein an outer peripheral length of a cross section orthogonal to a longitudinal direction of the exposed portion of the semiconductor core is shorter than an outer peripheral length of a cross section orthogonal to the longitudinal direction of the covered portion of the semiconductor core. A rod-shaped first conductive type semiconductor core;
A second-conductivity-type semiconductor layer covering a portion other than the exposed portion of the semiconductor core so as not to cover a portion on one end side of the semiconductor core;
With
Providing a step between the outer peripheral surface of the exposed portion of the semiconductor core that is not covered by the semiconductor layer and the outer peripheral surface of the covering portion of the semiconductor core that is covered by the semiconductor layer;
A rod-shaped structure light emitting element, wherein a shape of a cross section orthogonal to a longitudinal direction of the exposed portion of the semiconductor core is different from a shape of a cross section orthogonal to the longitudinal direction of the covered portion of the semiconductor core. A rod-shaped first conductive type semiconductor core;
A second-conductivity-type semiconductor layer covering a portion other than the exposed portion of the semiconductor core so as not to cover a portion on one end side of the semiconductor core;
With
Providing a step between the outer peripheral surface of the exposed portion of the semiconductor core that is not covered by the semiconductor layer and the outer peripheral surface of the covering portion of the semiconductor core that is covered by the semiconductor layer;
A cap layer formed to cover an end surface of the semiconductor core opposite to the exposed portion;
The said cap layer consists of material with a larger electrical resistance than the said semiconductor layer, The rod-shaped structure light emitting element characterized by the above-mentioned. In the rod-shaped structure light emitting element according to any one of claims 1 to 3 ,
A rod-like structure light emitting element, wherein a cross section of the semiconductor core perpendicular to the longitudinal direction of the covering portion is polygonal. In the rod-shaped structure light emitting element according to any one of claims 1 to 4,
A rod-shaped structure light emitting element characterized in that a cross section perpendicular to the longitudinal direction of the exposed portion of the semiconductor core is substantially circular. In the rod-shaped structure light emitting element according to any one of claims 1 to 5,
An insulating layer formed to cover the stepped portion of the semiconductor core and the end surface of the semiconductor layer on the stepped portion side, and to cover the stepped portion side of the exposed portion of the semiconductor core. A rod-shaped structure light emitting device characterized by the above. In the rod-shaped structure light emitting element according to any one of claims 1 to 6,
A rod-shaped structure light emitting element comprising a conductive layer formed so as to cover the semiconductor layer and made of a material having an electric resistance lower than that of the semiconductor layer. In the rod-shaped structure light emitting element according to any one of claims 1 to 7,
A rod-shaped structure light emitting device comprising a quantum well layer formed between the semiconductor core and the semiconductor layer. In the rod-shaped structure light emitting element according to any one of claims 1 to 8 ,
A rod-shaped structure light-emitting element, wherein the semiconductor core has a diameter of 500 nm or more and 100 μm or less. A rod-shaped structure light emitting device according to any one of claims 1 to 9 ,
A substrate on which the rod-shaped structure light emitting element is mounted so that the longitudinal direction of the rod-shaped structure light emitting element is parallel to the mounting surface;
Electrodes are formed on the substrate at predetermined intervals,
The exposed portion on one end side of the semiconductor core of the rod-shaped structure light emitting element is connected to one electrode on the substrate, and the semiconductor on the other end side of the semiconductor core is connected to the other electrode on the substrate. A light-emitting device, wherein layers are connected. A rod-shaped structure light emitting device according to claim 7,
A substrate on which the rod-shaped structure light emitting element is mounted so that the longitudinal direction of the rod-shaped structure light emitting element is parallel to the mounting surface;
Electrodes are formed on the substrate at predetermined intervals,
The exposed portion on one end side of the semiconductor core of the rod-shaped structure light emitting element is connected to one of the electrodes on the substrate, and the conductive portion on the other end side of the semiconductor core is connected to the other electrode on the substrate. A light-emitting device, wherein layers are connected. In the light-emitting device according to claim 1 1,
A light-emitting device comprising a second conductive layer formed on the conductive layer of the rod-shaped structure light emitting element and on the substrate side and made of a material having a lower electrical resistance than the semiconductor layer. In the light-emitting device according to any one of claims 1 0 to 1 2,
A light-emitting device comprising a metal portion formed between the electrodes on the substrate and below the rod-shaped structure light-emitting element. In the light-emitting device according to claim 1 3,
The metal part is formed on the substrate for each of the rod-shaped structure light emitting elements,
The light emitting device, wherein the metal parts of the bar-shaped light emitting elements adjacent to each other are electrically insulated. The method for manufacturing a light emitting device having the above-mentioned rod-like structure light emitting device according to claim 1, any one of 1 4,
A substrate creating step for creating an insulating substrate in which an array region having at least two electrodes each having an independent potential applied thereto is formed;
An application step of applying a liquid containing the rod-shaped structure light emitting element of nano-order size or micro-order size on the insulating substrate;
A method of manufacturing a light-emitting device, comprising: an arraying step of applying the independent voltages to the at least two electrodes, respectively, and arranging the rod-shaped structure light emitting elements at positions defined by the at least two electrodes. . Backlight comprising the rod-like structure element according to any one of claims 1 to 9. An illuminating device comprising the rod-shaped structure light emitting element according to any one of claims 1 to 9 . Display device characterized by comprising a rod structure element according to any one of claims 1 to 9.

Images