JP2005353828A - Light emitting element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting element that is high in light emitting efficiency, can select a light emitting wavelength depending upon the material used, and can emit light having the small half-value width of emission spectrum. <P>SOLUTION: The light emitting element is provided with a lower electrode 12, an upper electrode 18, a first semiconductor layer 13 formed on a substrate 11, a functional layer 14 formed on the first semiconductor layer 13, and a second semiconductor layer 17 formed on the functional layer 14. The functional layer 14 is provided with a first member 15 composed of a columnar semiconductor material formed perpendicularly or nearly perpendicularly to the first semiconductor layer 13, and a second member 16 formed to surround the first member 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light-emitting element and a method for manufacturing the light-emitting element, and more particularly to a light-emitting element and a method for manufacturing the light-emitting element that have high emission efficiency and can widely change the emission wavelength.

  The large-scale integrated circuits (LSIs) that form the basis of today's electronics have dramatically improved the performance of high-speed processing, large-capacity information recording, low power consumption, etc. due to the miniaturization of their element structures. The performance improvement is expected to continue with miniaturization.

  However, when miniaturization proceeds at the current pace and the element size becomes 70-60 nm or less, the limit of the operation principle of the conventional element is reached, and it becomes difficult to improve the performance only by simple miniaturization.

  In order to solve this problem, a new dielectric material other than silicon is introduced into the gate oxide film portion of an LSI MOS (Metal-Oxide-Semiconductor) transistor. Research on performance improvement by improving this part is conducted at a rapid pace.

  Apart from this approach, active research has been conducted in recent years to try to solve the above problem by using a new element based on a new operation principle different from the operation principle of a conventional MOS transistor. A typical example is a semiconductor element using a quantum size effect.

  This limits the degree of freedom of electrons in the semiconductor by confining the electrons in a semiconductor layer having a width comparable to the wavelength of electrons (de Broglie wavelength) by reducing the size of the device, and as a result, in the semiconductor The effect is that the density of states of electrons changes.

  In addition, the density of states changes depending on the shape of the miniaturized semiconductor, and the density of states is reduced to a low-dimensional shape such as two-dimensional (quantum well), one-dimensional (quantum wire), or zero-dimensional (quantum dot). Has been discretized, and as a result, the effect of improving the mobility of carriers has been derived by theoretical calculation.

  Among them, in a quantum wire which is a one-dimensional structure, a quantum effect appears by setting the diameter of the semiconductor wire to about 10 nm of the de Broglie wavelength, and the conduction carriers move in the thin wire with almost no scattering. be able to. For this reason, it is possible to manufacture a high-speed responsive transistor by forming a conductive layer in which a large number of quantum wires are arranged in a plane, and a highly efficient light-emitting element by using quantum wires as a light-emitting layer.

  In a high-efficiency light-emitting element using this quantum wire, increasing the density of the light-emitting layer is a problem. In the conventional method for producing quantum wires as disclosed in Patent Document 1, the quantum wires are arranged horizontally on the substrate surface. For this reason, the density of the quantum wires is determined by the accuracy of lithography at the time of producing the quantum wires, and it is difficult to increase the density.

  This can be solved by producing the quantum wires in the direction perpendicular to the substrate, but it is difficult to form this structure by the conventional methods for producing quantum wires using photolithography or etching.

  As a method for realizing a structure having a quantum wire structure in the direction perpendicular to the substrate, there is an example in which porous silicon is used as disclosed in Patent Document 2. In porous silicon, the porosity can be controlled by the concentration of hydrofluoric acid used for anodization, the temperature of the solution, the concentration of holes in the Si wafer, etc., and the crystalline Si region surrounding the pores is increased by increasing the porosity. It becomes a shape.

Since the pores are formed substantially perpendicular to the substrate, the fine lines are also formed perpendicularly. When porous silicon is used, when the pore size is 6 nm or less, it has been confirmed that a quantum effect appears and Si that does not emit light in the bulk emits photo-excited light emission / current injection light emission. Has been.
JP-A-5-29632 JP-A-6-13653

  However, in the light-emitting element in which Si is quantum thinned, since light is emitted by using a quantum thin wire structure that is originally difficult to emit light, the light emission efficiency is not high, and further improvement of the light emission efficiency has been desired. .

  In addition, since the emission wavelength varies depending on the size of the quantum wire, it is difficult to control the emission wavelength in the quantum wire produced by the above process, and the emission wavelength is limited because the material is limited to Si, A light emitting element capable of realizing a wide range of light emission wavelengths has been desired.

  In view of the above, an object of the present invention is to provide a light-emitting element that emits light with high emission efficiency, capable of selecting an emission wavelength depending on a material used, and having a small half-value width of an emission spectrum.

  In particular, another object of the present invention is to provide a light-emitting element having a large number of semiconductor quantum wires arranged perpendicular to the substrate by using a novel porous film.

  It is another object of the present invention to provide a method for manufacturing a light emitting element that has high luminous efficiency and can widely change the emission wavelength depending on the material used.

  In particular, another object of the present invention is to provide a method for manufacturing a light emitting device having a large number of semiconductor quantum wires arranged perpendicular to a substrate by using a novel porous film.

  As a means for solving the above problems, the present invention is formed on a substrate, an electrode, a first semiconductor layer, a functional layer formed on the first semiconductor layer, and the functional layer. The functional layer includes a first member made of a columnar semiconductor material formed perpendicularly or substantially perpendicular to the first semiconductor layer, and the second semiconductor layer. A second member formed to surround the one member is provided.

  In the present invention, the second member is characterized in that the main components excluding oxygen are aluminum and silicon, aluminum and germanium, or aluminum, silicon and germanium. And

  Further, the present invention is characterized in that the second member is an insulator.

  In the present invention, the first member has an average diameter of 1 nm to 10 nm and an average interval of 3 nm to 20 nm.

  In the present invention, the first semiconductor layer and the second semiconductor layer have different polarities.

  In the invention, it is preferable that the light emitting element is a light emitting diode.

  In addition, the present invention includes the above light-emitting element.

  In addition, the present invention provides a step of preparing an electrode on a substrate, a step of preparing a first semiconductor layer on the electrode, and a columnar substance including a first component, the first component and A step of preparing on the first semiconductor layer a structure dispersed in a member including a second component, which is a semiconductor material capable of forming a eutectic, and removing the columnar substance; A removal step of forming a porous body layer, a step of insulating a porous body having columnar pores obtained by the removal step, and a semiconductor material is filled in the columnar pores of the porous body A step of preparing a functional layer formed by the above, a step of preparing a second semiconductor layer on the functional layer, and a step of preparing an electrode on the second semiconductor layer, To do.

  In the invention, it is preferable that the first component is aluminum and the second component is any one of silicon, germanium, and a mixture of silicon and germanium.

  In the present invention, the first semiconductor layer and the second semiconductor layer have different polarities.

  According to the present invention, by making a semiconductor a quantum wire structure, carrier mobility is improved, and the probability of electron-hole recombination in the quantum wire semiconductor is improved.

  In addition, according to the present invention, it is possible to fabricate semiconductor quantum wires with high density by using a porous film having a through-hole perpendicular to the substrate, and the density of the light emitting portion is increased. Luminous efficiency can be improved and the half width of the emission wavelength spectrum can be reduced.

  In addition, according to the present invention, in the quantum wire light emitting device using porous silicon, the light emitting material is limited to silicon. However, in the present invention, basically any semiconductor can be filled in the porous film. A light-emitting element having a wide wavelength range can be manufactured.

  Moreover, according to the manufacturing method of the light emitting element which concerns on this invention, it becomes possible to manufacture the above light emitting elements.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  First, the main feature of the light emitting device according to the present invention is that a quantum wire structure is obtained by introducing a semiconductor material into a porous film having a high density of pores with a diameter of several nm that is perpendicular to the film surface. The semiconductor light emitting layer has a structure in which the semiconductor light emitting layers are arranged at high density and vertically.

[Description of configuration]
FIG. 1 is a cross-sectional view illustrating a configuration of a light emitting element as an embodiment of the present invention.

  In FIG. 1, 11 is a substrate, 12 is a lower electrode, 13 is a first semiconductor layer, 14 is a functional layer, 15 is a first member made of a columnar semiconductor constituting the functional layer 14, and 16 is a functional layer 14. A second member formed surrounding the first member constituting the structure, 17 is a second semiconductor layer, and 18 is an upper electrode.

  In this specification, “substantially perpendicular” refers to a state in which a columnar first member is in contact with a first semiconductor layer and a second semiconductor layer.

  First, the second member 16 constituting the functional layer 14 will be described.

  FIG. 2 is a perspective view for explaining the structure of the functional layer of the light emitting element of this embodiment.

  FIG. 2A is a diagram illustrating a stage where the columnar substance is formed, and FIG. 2B is a diagram illustrating a stage where the columnar substance is removed.

  The second member 16 constituting the functional layer 14 includes a second component that the columnar substance 21 including the first component shown in FIG. 2A can form a eutectic with the first component. The columnar substance 21 is removed from the structure thin film 23 dispersed in the base material substance 24 that is included. FIG. 2B is a diagram showing this state.

  Here, the columnar substance 21 including the first component is made of, for example, a material mainly composed of aluminum. The base material 24 including the second component that can form a eutectic with the first component is made of, for example, germanium, silicon, or a mixture of germanium and silicon. In particular, the base material 24 is preferably composed mainly of silicon or germanium. It is also possible to use a mixture of silicon and germanium as a main component.

  The base material 24 is preferably composed mainly of silicon or germanium, but aluminum (Al), oxygen (O), argon (Ar), nitrogen (N), hydrogen of several to several tens atomic%. It may contain an element such as (H).

  FIG. 3 is a diagram used for explaining the first member 15 constituting the functional layer of the present embodiment.

  FIG. 3A is a plan view when FIG. 2B is viewed from above, and FIG. 3B is a cross-sectional view taken along line BB in FIG. 3A.

  Further, the shape of the pore portion constituting the base material 24 viewed from the upper surface of the substrate may be substantially circular as shown in FIG. 3A, or may be of any shape such as an ellipse. Good.

  Further, the shape of the pore portion constituting the base material 24 as viewed from the cross section of the substrate may be a rectangular shape as shown in FIG. 3B, or an arbitrary shape such as a square or a trapezoid.

  In addition, the average diameter 2r of the pores shown in FIG. 3B is preferably 1 nm or more and 10 nm or less, and the average interval 2R is preferably 3 nm or more and 20 nm or less.

  Moreover, there is no restriction | limiting in the film thickness L of a porous thin film, Basically what kind of film thickness may be sufficient. However, the optimum film pressure varies depending on the material of the first member 15 made of a columnar semiconductor, and the probability that electrons and holes injected into the first member 15, that is, the columnar semiconductor material that is the light emitting portion, are combined. It is desirable to set the film thickness so as to increase.

  Next, the first member 15 made of a columnar semiconductor constituting the functional layer 14 will be described.

  The columnar semiconductor member 15 may basically be any semiconductor material, for example, a group IV semiconductor such as silicon (Si) or germanium (Ge), gallium-arsenic (GaAs), gallium- Group III-V semiconductors such as phosphorus (GaP), gallium-arsenic-phosphorus (GaAsP), gallium nitride (GaN), indium-phosphorus (InP), indium-gallium-phosphorus (InGaP), cadmium sulfide (CdS), cadmium -II-VI group semiconductors such as zinc-sulfur (CdZnS), zinc-selenium (ZnSe), cadmium-selenium (CdSe), cadmium-tellurium (CdTe), zinc sulfide (ZnS), and other semiconductors May be used.

  Among the semiconductor materials described above, a semiconductor material with high luminous efficiency is preferable, and specifically, GaAs, GaAsP, GaN, CdS, CdSe, ZnSe, ZnS, and the like are particularly preferable.

  More preferably, a semiconductor material that can fill the pores of the porous thin film by an electrodeposition method or a VLS (Vapor-Liquid-Solid) method is preferable.

  Further, since light is emitted by recombining electrons and holes in the columnar semiconductor member 15, the columnar semiconductor member 15 is an intrinsic semiconductor in which the concentrations of holes and electrons existing in the semiconductor are substantially equal. It is desirable. However, the conductivity type and the carrier concentration are not particularly limited as long as the carrier recombination light emission from the semiconductor member 15 is not hindered.

  Next, the first semiconductor layer 13 and the second semiconductor layer 17 will be described.

  Electrons and holes are injected into the columnar semiconductor member 15 from these two semiconductor layers. That is, the first semiconductor layer 13 and the second semiconductor layer 17 need to have different conductivity types. Moreover, since it is necessary to transmit the light emitted from the semiconductor member 15, any material may be used for the first semiconductor layer 13 and the second semiconductor layer 17, and the film thicknesses of each may be determined. May be set.

[Description of manufacturing method]
Next, the manufacturing method of the light emitting element as one embodiment of this invention is demonstrated.

  4 and 5 are cross-sectional views showing a method for manufacturing a light-emitting element as an embodiment of the present invention.

  Below, each process of one Embodiment of the manufacturing method of a light emitting element is shown. The manufacturing method of a light emitting element has the following (a)-(h) process.

(A) Step: Step of preparing an electrode on the substrate (b) Step: Step of preparing a first semiconductor layer on the electrode (c) Step: A columnar substance including the first component is first (D) Step: Columnar Substance A Step of Preparing a Structure Dispersed in a Member Containing and Containing a Second Component that is a Semiconductor Material That Can Form a Eutectic with a Component of (d) (E) step: step of insulating the porous body having columnar pores obtained by the removal step (f) step: columnar pores of the porous body Step of preparing a functional layer formed by filling a semiconductor material therein (g) Step: Step of preparing a second semiconductor layer on the functional layer (h) Step: Electrode on the second semiconductor layer Steps to be Prepared Each of the above steps will be described below with reference to FIGS. 4 and 5.

(A) Process: The electrode 412 is prepared on the board | substrate 411. FIG. Any electrode material may be used as long as it functions as an electrode. Specifically, what kind of materials are basically used such as metal electrodes such as Al, Ti, Pt, Au, and oxide transparent electrodes such as tin-doped indium oxide (Sn-doped In ₂ O ₃ : ITO). A material that forms ohmic contact with the semiconductor prepared in the step (b) is preferable. Further, any method such as sputtering or vapor deposition may be used as a method for manufacturing the electrode.

  (B) Step: A first semiconductor layer 421 is prepared on the electrode 412 prepared in the step (a). Basically, any semiconductor material can be used as long as it can be formed into a film.

  When a glass substrate is selected as the substrate and an oxide transparent electrode such as ITO is selected as the lower electrode to produce a structure in which light is extracted from the substrate side, the semiconductor layer prepared in this step is produced in the subsequent step (f). Although light emitted from the semiconductor material 462 needs to be transmitted, any material may be used as long as this condition is satisfied.

  As the film forming method, it is preferable to use a film forming method such as a plasma CVD method in which the conductivity type of the manufactured semiconductor film can be easily controlled and the surface of the film becomes smooth.

  (C) Step: A semiconductor material in which the columnar substance 432 including the first component can form a eutectic with the first component on the first semiconductor layer 421 prepared in the step (b). A structure layer 431 is prepared which is dispersed in a base material 433 including the second component. For example, aluminum and silicon (germanium, silicon, or a mixture of silicon and germanium) that forms a columnar material (first component) in the base material (second component) are prepared, and in a non-equilibrium state such as sputtering. A mixed film (aluminum silicon mixed film, aluminum germanium mixed film, or aluminum silicon germanium mixed film) which is a structure layer is formed on the first semiconductor layer by a method capable of forming a substance.

  When an aluminum silicon mixed film (aluminum germanium mixed film or aluminum silicon germanium mixed film) is formed by such a method, aluminum and silicon (germanium or a mixed film of silicon and germanium) become a metastable eutectic structure, and aluminum A columnar substance consisting of a nanostructure (columnar structure) of several nm level is formed in a base material made of amorphous silicon (amorphous germanium or a mixture of amorphous silicon and germanium) and is separated in a self-organizing manner. . At that time, the aluminum columnar substance has a substantially cylindrical shape, an average diameter 2r of 1 nm or more and 10 nm or less, and an average interval 2R of 3 nm or more and 20 nm or less.

  Note that in a mixed film of aluminum and amorphous silicon (amorphous germanium or a mixture of amorphous silicon and germanium), the amount of silicon (germanium or a mixture of silicon and germanium) in the formed film is aluminum and silicon (germanium). Or a mixture of silicon and germanium), preferably 20-70 atomic%, preferably 25-65 atomic%, more preferably 25-65 atomic%.

  If the amount of silicon is within the above range, an aluminum silicon mixed film (aluminum mixed film or aluminum silicon germanium) in which an aluminum columnar material is dispersed in an amorphous silicon (amorphous germanium or a mixture of amorphous silicon and germanium) base material. A mixed film) is obtained.

  The atomic% indicating the ratio of aluminum and silicon (germanium or a mixture of silicon and germanium) indicates the ratio of the number of atoms of silicon (germanium or a mixture of silicon and germanium) and aluminum, and is atom% or at%. For example, the amount of silicon (germanium or silicon / germanium) and aluminum in an aluminum silicon mixed film (aluminum germanium mixed film or aluminum silicon germanium mixed film) and aluminum in an inductively coupled plasma emission spectrometry (ICP method) This is the value when quantitative analysis is performed.

  (D) Process: The columnar substance 432 comprised including said 1st component is removed, and the porous body layer 441 which has the pore 442 is formed. For example, the columnar material aluminum in the aluminum silicon mixed film (aluminum germanium mixed film or aluminum silicon germanium mixed film) is removed by etching using phosphoric acid, and the inside of the base material (here, amorphous silicon, amorphous germanium is used). Alternatively, pores are formed in a mixture of amorphous silicon and germanium. Thereby, a porous body layer is formed on the first semiconductor layer.

  The pores 442 in the porous body layer have an average diameter 2r of 1 nm to 10 nm and an average interval 2R of 3 nm to 20 nm.

  The solution used for etching is preferably an acid which dissolves aluminum and hardly dissolves amorphous silicon (amorphous germanium or a mixture of amorphous silicon and germanium), for example, phosphoric acid, sulfuric acid, hydrochloric acid, sulfuric acid, concentrated sulfuric acid, chromic acid. Such as a solution.

  However, an alkali such as sodium hydroxide can be used as long as there is no problem in the formation of pores by etching, and it is not particularly limited to the type of acid or the type of alkali.

  Further, a mixture of several types of acid solutions or several types of alkali solutions may be used. In addition, as for the etching conditions, for example, the solution temperature, concentration, time, etc. can be appropriately set according to the porous body layer to be produced.

  (E) Process: The porous structure 443 having the pores 442 obtained by the removing process is made into an insulator, and a porous structure 453 having the pores 442 and the insulator porous body layer 451 is prepared.

  As an example of forming the porous structure 443 as an insulator, an oxidation treatment is given. The porous structure is made amorphous by subjecting the amorphous silicon (amorphous germanium or a mixture of amorphous silicon and germanium) to oxidize, for example, annealing in an oxygen atmosphere to the porous structure. Silicon (amorphous germanium or a mixture of amorphous silicon and germanium) oxidizes.

  As a result, a silicon oxide porous body layer (germanium oxide porous body layer or silicon oxide germanium porous body layer) is formed on the first semiconductor layer. At this time, heat treatment in an oxidizing atmosphere is preferable, for example, heat treatment in an oxygen atmosphere is preferable.

  Further, the heat treatment is desirably performed under conditions such that only the porous structure is oxidized, and is desirably performed at a temperature of 100 ° C. or higher and 800 ° C. or lower in the air or an oxygen atmosphere, and more preferably 200 ° C. or higher and 500 ° C. or lower. It is more desirable to carry out at a temperature of ℃ or less.

  However, in the structure of amorphous silicon (amorphous germanium or a mixture of amorphous silicon and germanium) and insulation silicon porous body layer (insulator germanium porous body layer or insulator silicon germanium porous body layer) If there is no problem, any method and conditions may be used for insulating the porous structure, and several methods may be used in combination.

  (F) Step: The semiconductor material is filled in the columnar pores 452 of the insulator porous body layer 451, and a functional layer 461 composed of the semiconductor material 462 and the insulator porous body layer 451 is prepared. The method of filling the semiconductor material into the insulator porous body layer may be basically any method. Examples of a method for filling the pores with a semiconductor material include an electrodeposition method and a VLS (Vapor-Liquid-Solid) method.

  (G) Step: A second semiconductor layer 471 is prepared on the functional layer 461. The second semiconductor layer prepared in this step needs to be made of a semiconductor material having a conductivity type different from that of the first semiconductor layer 421. Further, when a transparent electrode is selected as the electrode prepared in the step (h) and light is extracted from the element surface, the second semiconductor layer 471 manufactured in the step is the semiconductor material 462 prepared in the step (f). It is necessary to transmit the light emitted from. As long as the above conditions are satisfied, basically any substance may be used.

  As the film forming method, it is preferable to use a film forming method such as a plasma CVD method in which the conductivity type of the manufactured semiconductor film can be easily controlled and the film surface becomes smooth.

  Further, before the film formation in this step, a process of smoothing the functional layer surface by CMP polishing or the like may be performed.

  (H) Step: An electrode 481 is prepared on an n-type semiconductor layer 471. Any electrode material may be used, but an ohmic contact is formed with the second semiconductor layer 471 at the bottom. It is desirable to use materials. The electrode may be formed by any method such as sputtering or vapor deposition.

  The above is the configuration of the light-emitting conversion element and the manufacturing method thereof. However, unless the configuration and the manufacturing method of the photoelectric conversion element are significantly changed, the light emission used in the light-emitting diode and the semiconductor laser in addition to the element configuration. Devices for improving efficiency and making the emission wavelength monochromatic may be added to the structure of the light emitting element. In addition, a process for introducing a device into the manufacturing method may be added.

[Example]
Hereinafter, the above embodiment will be described with reference to examples.

(First embodiment)
In this example, a quartz substrate was used as the substrate.

Next, a titanium-silver (Ti-Ag) electrode is formed on the substrate by a sputtering method to a thickness of 100 nm, and phosphorus (P) is deposited on the upper portion of the substrate at a film forming temperature of 550 ° C. using a plasma CVD method. A doped n-type polycrystalline Si (poly-Si) thin film was formed to a thickness of 100 nm. At this time, the doping amount of phosphorus can be controlled by changing the ratio of the source gas SiH ₄ and the doping gas PH ₃ .

  Next, an aluminum silicon mixed film containing 56 atomic% of aluminum with respect to the total amount of aluminum and silicon was formed to a thickness of about 30 nm on the n-type polycrystalline silicon thin film by magnetron sputtering. A circular aluminum silicon mixed target having a diameter of 4 inches (101.6 mm) was used as the target.

  As the aluminum silicon mixed target, an aluminum powder and silicon powder sintered at a ratio of 56 atomic%: 44 atomic% was used. Sputtering conditions were as follows: RF flow rate, Ar flow rate: 30 sccm, discharge pressure: 0.15 Pa, input power: 100 W. The substrate temperature was 100 ° C.

  The aluminum silicon mixed film was observed with an FE-SEM (field emission scanning electron microscope). As a result, as shown in FIG. 2 (a), the shape of the surface viewed obliquely upward from the substrate was a two-dimensional array of circular aluminum columnar structures surrounded by silicon regions.

The average diameter of the aluminum columnar structure portion was 4 nm, and the average density was 1.5 × 10 ¹¹ cm ⁻² or more. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum silicon mixed film thus prepared was immersed in a phosphoric acid solution having a concentration of 5 weight percent for 24 hours, and only the aluminum columnar structure portion was selectively etched to form pores. Thereafter, in an oxygen atmosphere Heat treatment was performed at 500 ° C.

  When the shape was observed with an FE-SEM, it was a film having a large number of pores perpendicular to the film surface as shown in FIG. As a result, a porous film composed of a member whose main component excluding oxygen was silicon was produced. Under the above conditions, a sample in which only a porous film was produced on a quartz substrate was measured with a microscopic Raman spectroscope, and it was found to be silicon oxide.

Further, when an Al electrode was deposited on the porous film and the electrical conductivity of the porous sample surface was measured, it was 5 × 10 ⁻⁹ S · cm ⁻¹ , and the porous body became an insulator by the above treatment. It was confirmed that

Next, cadmium selenide (CdSe) was introduced into the pores of the porous body by electrodeposition. The electrolyte used was a solution of cadmium dichloride (CdCl ₂ ) and selenium (Se) in a solvent of 0.05 mol·L ⁻¹ cadmium dichloride (CdCl ₂ ) and dimethyl sulfoxide (DMSO). Electrodeposition was performed at a current temperature of 185 ° C. for 30 minutes at a current density of 0.85 mA · cm ⁻² .

  The film after electrodeposition was surface polished to smooth the surface. When the cross-sectional structure was observed by FE-SEM, it was confirmed that CdSe was filled in the pores of the porous body, and that a CdSe film was formed on the porous film. Further, it was confirmed by X-ray diffraction measurement that CdSe was present as crystals.

  An n-type poly-Si thin film was formed to a thickness of 100 nm by plasma CVD on the functional layer in which the pores in the porous film were filled with CdSe. The film forming temperature was 550 ° C., and boron (B) was doped to give p-type conductivity.

  Finally, an ITO transparent electrode as an upper electrode was formed to a thickness of 100 nm by a sputtering method.

  When an electric field of 5 V was applied in the forward direction to the device produced by the above method and measured with a spectrum analyzer, light emission around about 680 nm was confirmed. In addition, as shown in FIG. 6, the half-value width of the emission wavelength spectrum of the light emitting element using the functional layer is smaller than that of the light emitting element having a structure in which the functional layer portion in this structure is replaced with a CdSe film. It was confirmed that

(Second embodiment)
In this example, a quartz substrate was used as the substrate.

Next, a titanium-silver (Ti-Ag) electrode is formed on the substrate by a sputtering method to a thickness of 100 nm, and phosphorus (P) is deposited on the upper portion of the substrate at a film forming temperature of 550 ° C. using a plasma CVD method. A doped n-type polycrystalline Si (poly-Si) thin film was formed to a thickness of 100 nm. At this time, the doping amount of phosphorus can be controlled by changing the ratio of the source gas SiH ₄ and the doping gas PH ₃ .

  Next, an aluminum-silicon mixed film containing 56 atomic% of aluminum with respect to the total amount of aluminum and silicon was formed to a thickness of about 30 nm on the n-type polycrystalline silicon thin film by magnetron sputtering.

  A circular aluminum silicon mixed target having a diameter of 4 inches (101.6 mm) was used as the target. As the aluminum silicon mixed target, an aluminum powder and silicon powder sintered at a ratio of 56 atomic%: 44 atomic% was used. Sputtering conditions were as follows: RF flow rate, Ar flow rate: 30 sccm, discharge pressure: 0.15 Pa, input power: 100 W. The substrate temperature was 100 ° C.

  In addition, the aluminum silicon mixed film was observed with FE-SEM (field emission scanning electron microscope). As a result, as shown in FIG. 2A, the shape of the surface viewed from the obliquely upward direction of the substrate was a two-dimensional array of circular aluminum columnar structures surrounded by silicon regions.

The average diameter of the aluminum columnar structure portion was 4 nm, and the average density was 1.5 × 10 ¹¹ cm ⁻² or more. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum silicon mixed film thus prepared was immersed in a phosphoric acid solution having a concentration of 5 weight percent for 24 hours, and only the aluminum columnar structure portion was selectively etched to form pores. Thereafter, in an oxygen atmosphere Heat treatment was performed at 500 ° C.

  When the shape was observed with an FE-SEM, it was a film having a large number of pores perpendicular to the film surface as shown in FIG. As a result, a porous film composed of a member whose main component excluding oxygen was silicon was produced.

Under the above conditions, a sample in which only a porous film was produced on a quartz substrate was measured with a microscopic Raman spectroscope, and it was found to be silicon oxide. In addition, when an Al electrode was deposited on the porous film and the electrical conductivity of the surface of the porous sample was measured, it was 5 × 10 ⁻⁹ S · cm ⁻¹ or less. Confirmed that.

  Next, gold (Au) having a thickness of several nm was introduced into the pores of the porous film by an electrodeposition method. At that time, tungsten is used as an electrode when filling the pores with gold by electrodeposition. The porous thin film produced in the above process was placed in a commercially available electroplating solution (Electroplating solution for gold manufactured by High Purity Chemical Laboratory, product code K-24E), and kept in an acidic bath (pH = 4. 4). In 5), electrodeposition was performed at a current density of 0.5 A / dm2.

  Using the electrodeposited gold as a starting point, CdSe nanowires were grown in the pores of the porous film using a method called LCG (Laser-assisted-catalytic-growth) method.

  This method is a method of evaporating a material to form a nanowire by laser ablation and forming a nanowire by VLS (Vapor-Liquid-Solid) growth, and the diameter of the nanowire is the size of catalyst fine particles (in this case, gold fine particles). Determined by

  In this case, the nanowire diameter is determined by the size of the gold introduced into the pores of the porous membrane, that is, the pore diameter. As the nanowire grows, the deposited catalyst fine particles rise from the bottom of the pore to the top and move to the top of the porous film.

  CdSe nanowires were produced by the method described above. CdSe nanowires were grown at 700 ° C. for 10 minutes. Thereafter, the excessively grown CdSe nanowires and gold catalyst existing outside the pores were removed by surface polishing. When this shape was observed with FE-SEM, it was confirmed that almost all pores were filled with CdSe nanowires. Moreover, the peak resulting from CdSe appeared by X-ray diffraction, and it was found that the CdSe nanowires are crystalline.

  In addition, when the gold content change of the sample electrodeposited with gold in the pores and the sample polished on the surface after nanowire growth was measured by EDX, the peak intensity of gold decreased after the surface polishing. To confirm that the gold was removed.

  An n-type poly-Si thin film having a thickness of 100 nm was formed on the functional layer obtained by growing CdSe nanowires in the pores of the porous film by a plasma CVD method. The film forming temperature was 550 ° C., and boron (B) was doped to give p-type conductivity.

  Finally, an ITO transparent electrode as an upper electrode was formed to a thickness of 100 nm by a sputtering method.

  When an electric field of 5 V was applied in the forward direction to the device produced by the above method and measured with a spectrum analyzer, light emission around about 680 nm was confirmed.

  In addition, as shown in FIG. 6, the half-value width of the emission wavelength spectrum of the light emitting element using the functional layer is smaller than that of the light emitting element having a structure in which the functional layer portion in this structure is replaced with a CdSe film. It was confirmed that

(Third embodiment)
In this example, a quartz substrate was used as the substrate.

Next, a titanium-silver (Ti-Ag) electrode is deposited on the substrate to a thickness of 100 nm using a sputtering method, and phosphorus (P) is deposited on the top of the substrate at a deposition temperature of 550 ° C. using a plasma CVD method. A doped n-type polycrystalline Si (poly-Si) thin film was formed to a thickness of 100 nm. At this time, the doping amount of phosphorus can be controlled by changing the ratio of the source gas SiH ₄ and the doping gas PH ₃ .

  Next, an aluminum germanium mixed film containing 56 atomic% of aluminum with respect to the total amount of aluminum and germanium was formed on the n-type polycrystalline silicon thin film by magnetron sputtering to a thickness of about 30 nm.

  As a target, a circular aluminum germanium mixed target having a diameter of 4 inches (101.6 mm) was used. As the aluminum germanium mixed target, an aluminum powder and a germanium powder sintered at a ratio of 56 atomic%: 44 atomic% were used. Sputtering conditions were as follows: RF flow rate, Ar flow rate: 30 sccm, discharge pressure: 0.15 Pa, input power: 100 W. The substrate temperature was 100 ° C.

In addition, the aluminum germanium mixed film was observed with an FE-SEM (field emission scanning electron microscope). As a result, as shown in FIG. 2 (a), the shape of the surface viewed obliquely upward from the substrate was a two-dimensional array of circular aluminum columnar structures surrounded by germanium regions. The average diameter of the aluminum columnar structure portion was 10 nm, and the average density was 1.5 × 10 ¹⁰ cm ⁻² or more. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum germanium mixed film thus prepared is immersed in a concentrated sulfuric acid solution having a 98 percent concentration for 24 hours, and only aluminum columnar structure portions are selectively etched to form pores. Thereafter, in an oxygen atmosphere at 400 ° C. Heat-treated. When the shape was observed by FE-SEM, it was a film having many pores perpendicular to the film surface as shown in FIG.

As a result, a porous film composed of a member whose main component excluding oxygen was germanium was produced. Under the above conditions, a sample in which only a porous film was produced on a quartz substrate was measured with a microscopic Raman spectroscope, and it was found to be germanium oxide. Further, when an Al electrode was deposited on the porous film and the electrical conductivity of the surface of the porous sample was measured, it was 5 × 10 ⁻⁹ S · cm ⁻¹ or less. It was confirmed that

Next, cadmium selenide (CdSe) was introduced into the pores of the porous body by electrodeposition. The electrolyte used was a solution of cadmium dichloride (CdCl ₂ ) and selenium (Se) in a solvent of 0.05 mol·L ⁻¹ cadmium dichloride (CdCl ₂ ) and dimethyl sulfoxide (DMSO). Electrodeposition was performed at a current temperature of 185 ° C. for 30 minutes at a current density of 0.85 mA · cm ⁻² .

  The film after electrodeposition was surface polished to smooth the surface. When the cross-sectional structure was observed by FE-SEM, it was confirmed that CdSe was filled in the pores of the porous body, and that a CdSe film was formed on the porous film. Further, it was confirmed by X-ray diffraction measurement that CdSe was present as crystals.

  An n-type poly-Si thin film having a thickness of 100 nm was formed on the functional layer in which pores in the porous film were filled with CdSe by plasma CVD. The film forming temperature was 550 ° C., and boron (B) was doped to give p-type conductivity.

  Finally, an ITO transparent electrode as an upper electrode was formed to a thickness of 100 nm by a sputtering method.

  When an electric field of 5 V was applied in the forward direction to the device produced by the above method and measured with a spectrum analyzer, light emission around about 680 nm was confirmed. In addition, as shown in FIG. 6, the half-value width of the emission wavelength spectrum of the light emitting element using the functional layer is smaller than that of the light emitting element having a structure in which the functional layer portion in this structure is replaced with a CdSe film. It was confirmed that

(Fourth embodiment)
In this example, a quartz substrate was used as the substrate.

Next, a titanium-silver (Ti-Ag) electrode is formed on the substrate by a sputtering method to a thickness of 100 nm, and phosphorus (P) is deposited on the upper portion of the substrate at a film forming temperature of 550 ° C. using a plasma CVD method. A doped n-type polycrystalline Si (poly-Si) thin film was formed to a thickness of 100 nm. At this time, the doping amount of phosphorus can be controlled by changing the ratio of the source gas SiH ₄ and the doping gas PH ₃ .

  Next, an aluminum silicon germanium mixed film containing 56 atomic% of aluminum with respect to the total amount of aluminum, silicon, and germanium was formed on the n-type polycrystalline silicon thin film by magnetron sputtering to a thickness of about 30 nm. As the target, a circular aluminum silicon germanium mixed target having a diameter of 4 inches (101.6 mm) was used.

  As the aluminum silicon germanium mixed target, an aluminum powder, silicon powder, and germanium powder sintered at a ratio of 56 atomic%: 22 atomic%: 22 atomic% were used. Sputtering conditions were as follows: RF flow rate, Ar flow rate: 30 sccm, discharge pressure: 0.15 Pa, input power: 100 W. The substrate temperature was 100 ° C.

In addition, the aluminum silicon germanium mixed film was observed with FE-SEM (field emission scanning electron microscope). As a result, as shown in FIG. 2A, the circular shape of the aluminum columnar structures surrounded by the silicon germanium region was two-dimensionally arranged as seen from the diagonally upward direction of the substrate. The average diameter of the aluminum columnar structure portion was 7 nm, and the average density was 5.0 × 10 ¹⁰ cm ⁻² or more. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum silicon germanium mixed film thus prepared is immersed in a concentrated sulfuric acid solution of 98 percent concentration for 24 hours, and only aluminum columnar structure portions are selectively etched to form pores, and thereafter, 400 ° C. in an oxygen atmosphere. And heat-treated.

  When the shape was observed by FE-SEM, it was a film having many pores perpendicular to the film surface as shown in FIG. As a result, a porous film composed of a member whose main component excluding oxygen was silicon germanium was produced.

Under the above conditions, a sample in which only a porous film was produced on a quartz substrate was measured with a microscopic Raman spectroscope, and it was found that the porous body was an oxide of a silicon germanium compound. In addition, when an Al electrode was deposited on the porous film and the electrical conductivity of the surface of the porous sample was measured, it was 5 × 10 ⁻⁹ S · cm ⁻¹ or less. Confirmed that.

Next, cadmium selenide (CdSe) was introduced into the pores of the porous body by electrodeposition. The electrolyte used was a solution of cadmium dichloride (CdCl ₂ ) and selenium (Se) in a solvent of 0.05 mol·L ⁻¹ cadmium dichloride (CdCl ₂ ) and dimethyl sulfoxide (DMSO). Electrodeposition was performed at a current temperature of 185 ° C. for 30 minutes at a current density of 0.85 mA · cm ⁻² .

  The film after electrodeposition was surface polished to smooth the surface. When the cross-sectional structure was observed by FE-SEM, it was confirmed that CdSe was filled in the pores of the porous body, and that a CdSe film was formed on the porous film. Further, it was confirmed by X-ray diffraction measurement that CdSe was present as crystals.

  An n-type poly-Si thin film was formed to a thickness of 100 nm by plasma CVD on the functional layer in which the pores in the porous film were filled with CdSe. The film forming temperature was 550 ° C., and boron (B) was doped to give p-type conductivity.

  Finally, an ITO transparent electrode as an upper electrode was formed to a thickness of 100 nm by a sputtering method.

  When an electric field of 5 V was applied in the forward direction to the device produced by the above method and measured with a spectrum analyzer, light emission around about 680 nm was confirmed. In addition, as shown in FIG. 6, the half-value width of the emission wavelength spectrum of the light emitting element using the functional layer is smaller than that of the light emitting element having a structure in which the functional layer portion in this structure is replaced with a CdSe film. It was confirmed that

  A display device can be manufactured using the light-emitting element as a light-emitting source. A simple display device can be manufactured if a light emitting element is used as a light emitting source and a means for applying a voltage for light emission and a panel for displaying light emitted from the light emitting element are provided.

  In the present invention, the light-emitting element can be downsized, whereby a smaller display device can be manufactured.

It is sectional drawing which shows the structure of the light emitting element as one embodiment of this invention. It is a perspective view for demonstrating the structure of the functional layer of the light emitting element as one embodiment of this invention. It is a figure used in order to explain the 1st member 15 which constitutes the functional layer of one embodiment of the present invention. It is sectional drawing which shows the manufacturing method of the light emitting element as one embodiment of this invention. It is sectional drawing which shows the manufacturing method of the light emitting element as one embodiment of this invention. It is sectional drawing which shows the cross section of an example of the light emitting element used in order to compare performance with the light emitting element as one embodiment of this invention.

Explanation of symbols

11, 22, 33, 411, 51 ... substrate 12, 52 ... lower electrode 18, 56 ... upper electrode 412, 481 ... electrode 13, 421 ... first Semiconductor layer 17, 471 ... Second semiconductor layer 462 ... Semiconductor material 14, 461 ... Functional layer 15 ... First member 16 ... Second member 21, 432 ··· Columnar material 23 ··· Structure thin film 24, 32, 433 ··· Base material 25, 441 · · · Porous thin film 26, 31, 442, 452 ··· Fine Hole 431... Structure layer 443, 453... Porous structure 451... Insulator porous structure 53.
54... CdSe semiconductor layer replacing functional layer 55... N-type polycrystalline Si

Claims (10)

In a light-emitting element including an electrode, a first semiconductor layer, a functional layer formed on the first semiconductor layer, and a second semiconductor layer formed on the functional layer on a substrate,
The functional layer includes a first member made of a columnar semiconductor material formed perpendicularly or substantially perpendicular to the first semiconductor layer, and a second member formed surrounding the first member. A light-emitting element comprising: 2. The second member according to claim 1, wherein the main components excluding oxygen are either aluminum and silicon, aluminum and germanium, or aluminum, silicon and germanium. Light emitting element. The light emitting device according to claim 1, wherein the second member is an insulator. 4. The light-emitting element according to claim 1, wherein the first member has an average diameter of 1 nm to 10 nm and an average interval of 3 nm to 20 nm. 5. The light-emitting element according to claim 1, wherein the first semiconductor layer and the second semiconductor layer have different polarities. The light emitting device according to claim 1, wherein the light emitting device is a light emitting diode. An apparatus comprising the light emitting device according to claim 6. Preparing an electrode on a substrate;
Providing a first semiconductor layer on the electrode;
A structure in which a columnar substance including a first component is dispersed in a member including a second component, which is a semiconductor material capable of forming a eutectic with the first component, Preparing on the first semiconductor layer;
Removing the columnar substance to form a porous body layer; and
A step of insulating the porous body having columnar pores obtained by the removing step;
Preparing a functional layer formed by filling a semiconductor material in the columnar pores of the porous body;
Preparing a second semiconductor layer on the functional layer;
And a step of preparing an electrode on the second semiconductor layer. 9. The method for manufacturing a light-emitting element according to claim 8, wherein the first component is aluminum, and the second component is any one of silicon, germanium, and a mixture of silicon and germanium. The method for manufacturing a light-emitting element according to claim 9, wherein the first semiconductor layer and the second semiconductor layer have different polarities.

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