TWM627153U - Photonic crystal surface-emitting laser - Google Patents

Abstract

A photonic crystal surface-emitting laser including a distributed Bragg reflector (DBR), an active layer, a photonic crystal layer, a first electrode, a second electrode, and a transparent conductive layer is provided. The active layer is disposed on the DBR. The photonic crystal layer is disposed on the DBR. The first electrode is electrically connected to one side of the active layer. The second electrode is electrically connected to another side of the active layer. The transparent conductive layer is disposed between the active layer and the second electrode. The second electrode is electrically connected to the active layer through the transparent conductive layer. Light emitted by the active layer is reflected by the DBR and outputted from a light output surface of the photonic crystal surface-emitting laser opposite to the DBR.

Description

Photonic crystal surface emitting laser

This novel creation is about a laser, and especially about a photonic crystal surface-emitting laser (PCSEL).

The electroluminescent photonic crystal surface-emitting laser can achieve single mode output, narrow spectral wavelength linewidth and small light divergence angle, and its main structure includes a bottom cladding layer ( bottom cladding layer), an active layer and a photonic crystal layer, wherein the active layer is located between the bottom cladding layer and the photonic crystal layer. Under this structure and operation mechanism, the laser light will be emitted from two directions, such as the top and the bottom, to the outside world.

In this way, when the laser light emitted by the conventional electroluminescent photonic crystal surface-emitting laser is used in one direction, only half of the laser energy will be utilized, so that the utilized optical power is relative to the applied light power. The current slope efficiency of the electroluminescent photonic crystal surface emitting laser is low, which will result in wasted energy.

The novel creation provides a photonic crystal surface-emitting laser with better energy utilization.

An embodiment of the present invention provides a photonic crystal surface-emitting laser, including a distributed Bragg reflector (DBR), an active layer, a photonic crystal layer, a first electrode, a second electrode and a transparent conductive layer. The active layer is arranged on the distributed Bragg mirror, and the photonic crystal layer is arranged on the distributed Bragg mirror. The first electrode is electrically connected to one side of the active layer, and the second electrode is electrically connected to the other side of the active layer. The transparent conductive layer is disposed between the active layer and the second electrode, wherein the second electrode is electrically connected to the active layer through the transparent conductive layer. The light emitted by the active layer is reflected by the distributed Bragg reflector, and is emitted from a light exit surface of the photonic crystal surface-emitting laser that is opposite to the distributed Bragg reflector.

In the photonic crystal surface-emitting laser of the embodiment of the present invention, the first electrode and the second electrode are used to provide current to make the active layer emit light, and the distributed Bragg reflector is used to convert the light emitted by the active layer. Light is reflected to one side, so the photonic crystal surface-emitting laser of the embodiment of the present invention has better energy utilization.

100, 100a, 100b, 100c: Photonic crystal surface-emitting lasers

105: light-emitting surface

110: Distributed Bragg Mirror

120: Active layer

122: Light

130, 130c: Photonic crystal layer

131: Through hole

132, 132b: Coating layer

134, 134a, 134b: Ohmic contact layers

140: First electrode

150: Second electrode

152, 182: Opening

160: Substrate

170: Transparent conductive layer

180: Current limiting layer

190, 190a': Optical phase control layer

190a: N-type semiconductor layer

A, B: sample

C: District

D: Plateau area

L: distance

P1, P2, P3: point

QW#1, QW#2, QW#3: Luminescence spectrum

R: reflectance spectrum

1 is a cross-section of a photonic crystal surface-emitting laser according to an embodiment of the novel creation face diagram.

FIG. 2 is a graph showing the relationship between the resonance notch wavelength of the photonic crystal surface-emitting laser of FIG. 1 and the thickness of the optical phase control layer.

FIG. 3A is a diagram showing the three quantum well layers of the active layer after the resonance cavity modulation is performed when the resonance notch wavelength and the thickness of the optical phase control layer of the photonic crystal surface-emitting laser of FIG. 1 are at point P1 in FIG. 2 . Comparison plot of the spectrum relative to the reflectance spectrum of a distributed Bragg mirror.

FIG. 3B is a diagram showing the three quantum well layers of the active layer after the resonance cavity modulation is performed when the resonance notch wavelength and the thickness of the optical phase control layer of the photonic crystal surface emitting laser of FIG. 1 are at point P2 in FIG. 2 . Comparison plot of the spectrum relative to the reflectance spectrum of a distributed Bragg mirror.

FIG. 3C is a diagram showing the resonant cavity modulation of the three quantum well layers of the active layer when the resonance notch wavelength and the thickness of the optical phase control layer of the photonic crystal surface emitting laser of FIG. 1 are at point P3 in FIG. 2 . Comparison plot of the spectrum relative to the reflectance spectrum of a distributed Bragg mirror.

4A is a schematic cross-sectional view of a photonic crystal surface-emitting laser according to another embodiment of the novel creation.

4B is a schematic cross-sectional view of a photonic crystal surface-emitting laser according to another embodiment of the novel creation.

4C is a schematic cross-sectional view of a photonic crystal surface-emitting laser according to yet another embodiment of the novel creation.

Fig. 5 is the curve of the output light intensity of sample A and sample B with respect to the input power picture.

FIG. 1 is a schematic cross-sectional view of a photonic crystal surface-emitting laser according to an embodiment of the novel invention. Referring to FIG. 1 , the photonic crystal surface-emitting laser 100 of this embodiment includes a distributed Bragg mirror 110 , an active layer 120 , a photonic crystal layer 130 , a first electrode 140 and a second electrode 150 . The active layer 120 is disposed on the distributed Bragg mirror 110 . The active layer 120 is, for example, a quantum well layer, a multiple quantum well layer or a quantum dot layer, that is, a light emitting layer. The photonic crystal layer 130 is disposed on the distributed Bragg mirror 110 . In this embodiment, the photonic crystal layer 130 is disposed on the active layer 120 , that is, the photonic crystal layer 130 is disposed on the distributed Bragg mirror 110 by the active layer 120 , wherein the photonic crystal layer 130 is located on the photonic crystal surface-emitting laser between a light emitting surface 105 of the emitter 100 and the active layer 120 . The first electrode 140 is electrically connected to one side of the active layer 120, for example, to the distributed Bragg mirror 110 in this embodiment, and the second electrode 150 is electrically connected to the other side of the active layer 120, In this embodiment, for example, it is electrically connected to the photonic crystal layer 130 . The light 122 emitted by the active layer 120 generates resonance in the horizontal direction in FIG. 1 in the photonic crystal layer 130 , and the photonic crystal layer 130 may include a second-order grating structure, which directs the light 122 to the vertical direction in FIG. 1 . Direction guide, and transfer to the top and bottom in Figure 1. In addition, the structure of the second-order grating can be a structure with a two-dimensional hole array. In other embodiments, the photonic crystal layer 130 may also be a grating structure with a third or higher order, and in addition, the photonic crystal layer 130 may also be a one-dimensional grating structure. Go to Figure 1 The light 122 transmitted from the top in FIG. 1 exits from the light exit surface 105 and leaves the photonic crystal surface-emitting laser 100, while the light 122 transmitted to the bottom in FIG. 1 is reflected by the distributed Bragg mirror 110 and transmitted upward, and The light is emitted from the light exit surface 105 of the photonic crystal surface-emitting laser 100 relative to the distributed Bragg mirror 110 . The light 122 emitted from the light emitting surface 105 is the laser beam.

In this embodiment, the distributed Bragg mirror 110 is, for example, an N-type semiconductor layer, and the photonic crystal layer 130 is, for example, a P-type semiconductor layer. Therefore, when a forward voltage is applied to the first electrode 140 and the second electrode 150 , the active The layer 120 generates the recombination of electron-hole pairs, thereby emitting light 122, so the photonic crystal surface emitting laser 100 may be an electroluminescent laser. However, in other embodiments, the distributed Bragg mirror 110 may also be a P-type semiconductor layer, and the photonic crystal layer 130 may be an N-type semiconductor layer.

In the photonic crystal surface-emitting laser 100 of the present embodiment, the active layer 120 emits light because the first electrode 140 and the second electrode 150 are used to provide current, and the distributed Bragg reflector 110 is used for the active layer 120 to emit light. The emitted light 122 is reflected toward one side (for example, toward the top of FIG. 1 ), and is combined with the light 122 emitted by the active layer 120 toward the top of FIG. 1 . Therefore, the photonic crystal surface-emitting laser 100 of this embodiment has The better energy utilization rate is about twice that of the conventional electroluminescent photonic crystal surface-emitting laser. Specifically, under the design of the ideal film thickness, the reflectivity of the distributed Bragg mirror 110 is almost 100%. If the thickness of the optical phase control layer 190 described in the context is optimized, the photonic crystal surface of this embodiment is The energy utilization rate of the radiation type laser 100 can be close to that of the conventional electroluminescent photonic crystal surface radiation. type lasers twice.

In this embodiment, the photonic crystal surface-emitting laser 100 further includes a substrate 160 disposed between the distributed Bragg mirror 110 and the first electrode 140, wherein the substrate 160 can be electrically connected to the first electrode 140 and the distribution Type Bragg reflector 110.

The photonic crystal surface emitting laser 100 may further include a transparent conductive layer 170 disposed between the active layer 120 and the second electrode 150 , wherein the second electrode 150 is electrically connected to the active layer 120 through the transparent conductive layer 170 . The transparent conductive layer 170 can cover the photonic crystal layer 130 and is electrically connected to the second electrode 150 and the photonic crystal layer 130 , wherein the light exit surface 105 is the surface of the transparent conductive layer 170 facing away from the distributed Bragg mirror 110 . In this embodiment, the second electrode 150 has an opening 152 exposing the light-emitting surface 105 . In this embodiment, the photonic crystal surface emitting laser 100 further includes a current confinement layer 180 disposed between the photonic crystal layer 130 and the transparent conductive layer 170 and having an opening 182, wherein the transparent conductive layer 170 passes through the opening 182 is connected to the photonic crystal layer 130 .

In this embodiment, the photonic crystal layer 130 includes a cladding layer 132 and an ohmic contact layer 134 , and the cladding layer 132 is disposed on the active layer 120 . The ohmic contact layer 134 is disposed between the cladding layer 132 and the transparent conductive layer 170, and is in contact with the transparent conductive layer 170 to form an ohmic contact, wherein the cladding layer 132 and the ohmic contact layer 134 have a photonic crystal structure. For example, the photonic crystal layer 130 has a plurality of through holes 131 located in the cladding layer 132 and the ohmic contact layer 134 and extending from the cladding layer 132 to the ohmic contact layer 134 to form a photonic crystal structure. In this embodiment, the through hole 131 penetrates through the ohmic contact layer 134 and the cladding layer 132 . Furthermore, in an implementation For example, the through holes 131 may be arranged in a two-dimensional array in a direction parallel to the substrate 160 .

In this embodiment, the photonic crystal surface-emitting laser 100 further includes an optical phase control layer 190 disposed between the distributed Bragg mirror 110 and the active layer 120 . The thickness of the optical phase control layer 190 is used to control the reflection of the light 122 emitted by the active layer 120 between the distributed Bragg mirror 110 and the light exit surface 105 at the resonance dip wavelength falling on the distributed Bragg mirror 110 The wavelength range corresponding to the plateau region of the spectrum.

Specifically, FIG. 2 is a graph showing the relationship between the resonance notch wavelength of the photonic crystal surface-emitting laser of FIG. 1 and the thickness of the optical phase control layer. FIG. 3A is a diagram showing the three quantum well layers of the active layer after the resonance cavity modulation is performed when the resonance notch wavelength and the thickness of the optical phase control layer of the photonic crystal surface-emitting laser of FIG. 1 are at point P1 in FIG. 2 . Comparison of the reflectance spectra R of the spectra QW#1, QW#2, QW#3 with respect to the distributed Bragg mirrors. FIG. 3B is a diagram showing the three quantum well layers of the active layer after the resonance cavity modulation is performed when the resonance notch wavelength and the thickness of the optical phase control layer of the photonic crystal surface emitting laser of FIG. 1 are at point P2 in FIG. 2 . Comparison of the reflectance spectra R of the spectra QW#1, QW#2, QW#3 with respect to the distributed Bragg mirrors. FIG. 3C is a diagram showing the resonant cavity modulation of the three quantum well layers of the active layer when the resonance notch wavelength and the thickness of the optical phase control layer of the photonic crystal surface emitting laser of FIG. 1 are at point P3 in FIG. 2 . Comparison of the reflectance spectra R of the spectra QW#1, QW#2, QW#3 with respect to the distributed Bragg mirrors. In FIGS. 3A to 3C , the heights of the spectra QW#1, QW#2, and QW#3 of the three quantum well layers of the active layer 120 after being modulated by the resonant cavity in the direction of the vertical axis can be represented by the electric field on the right side of the figure. strength is measured, while distributed distribution The height of the reflectance spectrum R curve of the Lager mirror 110 in the direction of the vertical axis can be measured by the reflectance on the left side of the drawing. Please refer to FIG. 1 and FIG. 2 first, as shown in FIG. 2 , different thicknesses of the optical phase control layer 190 may produce different resonance notch wavelengths, and with the increase of the thickness of the optical phase control layer 190 , the resonance notch wavelengths There are also high and low oscillations. This phenomenon occurs because the distance L between the light-emitting surface 105 and the distributed Bragg mirror 110 forms a resonant cavity length similar to that of a Fabry-Perot etalon. The thickness of 190 is different, and the distance L is also different, so the resonance notch wavelength can be adjusted.

When the resonance notch wavelength falls in the C region in FIG. 2 (point P1 in FIG. 2 ), the spectra QW#1, QW#2, QW#3 of the three quantum well layers of the active layer 120 after being modulated by the resonant cavity The peak of the peak falls within the wavelength range corresponding to the plateau region D of the reflection spectrum of the distributed Bragg mirror 110, and the region C is also the original emission wavelength of the three quantum well layers of the active layer 120 when they have not been modulated by the resonant cavity. In the range, for example, the difference between the photon energy corresponding to the resonance notch wavelength and the photon energy corresponding to the original peak wavelength emitted by the material of the active layer 120 is less than 15meV, preferably less than 10meV. In one embodiment, the resonance notch wavelength falls within a wavelength range corresponding to the half-maximum width of the light emission spectrum of the material of the active layer 120 . Therefore, when the wavelength of the resonance notch falls in the C region, the luminous efficiency is the best, and the distributed Bragg reflector 110 has a high reflection efficiency for the light 122 emitted by the active layer 120, so the light 122 can be increased from the light emitting surface 105. ratio, thereby improving the light energy utilization rate of the photonic crystal surface-emitting laser 100 . When the resonance notch wavelength falls outside the C region in Figure 2 (such as the P2 and P3 points in Figure 2), the three quantum wells in the active layer At least a part of the peaks of the spectra QW#1, QW#2, QW#3 after the layers are modulated by the resonant cavity fall outside or at the edge of the plateau region D of the reflection spectrum of the distributed Bragg mirror 110, resulting in the distributed Bragg mirror The reflection efficiency of the light 122 emitted by the active layer 120 by 110 is poor, so that the proportion of the light 122 emitted from the light-emitting surface 105 is reduced, and at this time, the three quantum well layers whose resonance notch wavelength falls in the active layer 120 have not been subjected to resonance cavity tuning. The time-varying original luminescence wavelength is outside the range, resulting in poor luminous efficiency. Therefore, an appropriate distance L will help to improve the utilization rate of light energy of the photonic crystal surface-emitting laser 100 , and is related to the wavelength of the light 122 . The wavelength of light is different, and the appropriate distance L is also different. In addition, by using the optical phase control layer 190 and adjusting its growth thickness, it is helpful to generate an appropriate distance L. However, in another embodiment, the optical phase control layer 190 may not be used, but the active layer 120 can be in contact with the distributed Bragg mirror 110, and the active layer 120, the photonic crystal layer 130 and the transparent conductive layer are properly controlled by controlling the active layer 120. The thickness of the layer 170 is used to generate an appropriate distance L, so that the resonance notch wavelength of the light 122 emitted by the active layer 120 between the distributed Bragg mirror 110 and the light exit surface 105 falls within the reflection spectrum of the distributed Bragg mirror 110. within the wavelength range corresponding to the plateau region.

In this embodiment, the optical phase control layer 190 is an N-type semiconductor layer, and the photonic crystal layer 130 is a P-type semiconductor layer. However, in other embodiments, the optical phase control layer 190 may also be a P-type semiconductor layer, and the photonic crystal layer 130 may be an N-type semiconductor layer. In other embodiments, the photonic crystal layer 130 and the optical phase control layer 190 can be located on the same side of the active layer 120 and are both N-type semiconductor layers or P-type semiconductor layers. In addition, in other embodiments, the photonic crystal layer 130, the optical phase control layer 190 and the distributed Bragg mirror 110 may be located on the same side of the active layer 120, and may be both N-type semiconductor layers or P-type semiconductor layers.

The present invention does not limit the material of each film layer, nor does it limit the wavelength of the light 122 emitted by the active layer 120 . The wavelength of the light 122 emitted by the active layer 120 may be visible light, infrared light or ultraviolet light, and the invention is not limited to this. In some embodiments, the material of the substrate 160 may be gallium nitride (GaN), gallium arsenide (GaAs), indium phosphide (InP), gallium antimonide (GaSb) ) or other suitable material. The distributed Bragg mirror 110 is, for example, a multilayer film with alternating or periodically varying characteristics (eg, refractive index or thickness). For example, the distributed Bragg reflector 110 is a multi-layer film in which aluminum gallium arsenide (AlGaAs) layers with a high aluminum molar ratio and aluminum gallium arsenide layers with a low aluminum molar ratio are alternately stacked , A multilayer film in which aluminum nitride layers and gallium nitride layers are alternately stacked, a multi-layer film in which titanium dioxide (TiO ₂ ) layers and silicon dioxide (SiO ₂ ) layers are alternately stacked, and the aluminum molar ratio is high. A multilayer film, an aluminum gallium nitride (AlGaN) layer and a nitrogen oxide layer are alternately stacked with aluminum gallium arsenide (AlGaAsSb) layers and aluminum gallium antimonide (AlGaAsSb) layers with a lower Al molar fraction. A multilayer film in which gallium nitride (GaN) layers are alternately stacked, a multi-layer film in which indium gallium arsenide phosphide (InGaAsP) layers and indium phosphide (InP) layers are alternately stacked, or other suitable materials Stacked multilayer films. In one embodiment, the distributed Bragg mirror 110 may include a plurality of first aluminum gallium arsenide layers and a plurality of second aluminum gallium arsenide layers stacked alternately from the bottom to the top of FIG. 1 , wherein the first arsenide is The chemical formula of the aluminum gallium layer is Al _x1 Ga _y1 As, and the chemical formula of the second aluminum gallium arsenide layer is Al _x2 Ga _y2 As, where x1+y1=1, x2+y2=1 and x1<x2, and the first arsenic The refractive index of the aluminum gallium arsenide layer is higher than that of the second aluminum gallium arsenide layer. For example, in one embodiment, 0<x1<0.5, and 0.5≦x2<1. The material of the active layer 120 may include gallium nitride, aluminum gallium nitride (AlGaN), gallium arsenide, indium gallium arsenide (InGaAs), aluminum gallium arsenide (AlGaAs) , gallium phosphide (GaP), indium arsenide (InAs), indium arsenic antimonide (InAsSb), indium gallium arsenic antimonide (InGaAsSb), arsenic antimonide Aluminum gallium (aluminum gallium arsenic antimonide, AlGaAsSb), indium gallium arsenide phosphide (InGaAsP), aluminum indium gallium arsenide (aluminum indium gallium arsenide, AlInGaAs), other suitable semiconductor materials or combinations thereof, and active The layer 120 may adopt two or more different materials or two or more materials of the same compound but with different element ratios to form a quantum well layer, various quantum well layers or quantum dot structures.

The material of the optical phase control layer 190 and the cladding layer 132 is, for example, aluminum gallium arsenide (AlGaAs), gallium arsenide, aluminum gallium nitride, aluminum gallium indium arsenide (AlGaInAs), phosphorus Aluminum gallium indium phosphide (AlGaInP), aluminum gallium arsenide antimonide, indium gallium arsenide (InGaAs) or other suitable materials.

The material of the ohmic contact layer 134 may be gallium nitride, gallium arsenide, indium gallium arsenide phosphide (InGaAsP), indium gallium arsenide (InGaAs) or other suitable materials. In addition, the ohmic contact layer 134 can be heavily doped with beryllium, carbon, zinc or a combination thereof to form P-type doping, so as to have a good ohmic contact with the transparent conductive layer 170, wherein beryllium is doped The concentration of zinc may be about 10 ¹⁹ cm ^-3 , the carbon doping concentration may be about 10 ¹⁹ cm ^-3 to 10 ²⁰ cm ^-3 , and the zinc doping concentration may be about 10 ¹⁹ cm ^-3 to 10 ²⁰ cm ^{- 3} , but the new creation is not limited to this. The material of the current confinement layer 180 can be silicon nitride, silicon oxide or other suitable materials. The current confinement layer 180 can block current, so that the current can be concentrated at the opening 182 and pass through the opening 182 .

The material of the transparent conductive layer 170 is, for example, indium tin oxide (ITO), antimony tin oxide (ATO), fluorine doped tin oxide (FTO), aluminum zinc (aluminum oxide) zinc oxide (AZO), gallium zinc oxide (GZO), indium zinc oxide (IZO), zinc oxide (zinc oxide, ZnO), graphene (graphene) or other suitable transparent conductive materials. The first electrode 140 and the second electrode 150 can be metal electrodes, such as gold, titanium-gold alloy, titanium-platinum-gold alloy, nickel-germanium-gold alloy or other suitable metals. The transparent conductive layer 170 can conduct current to concentrate the current through the opening 182 , and at the same time, the transparent conductive layer 170 can also allow the light 122 emitted by the active layer 120 to penetrate without blocking the light 122 .

In addition, in an embodiment, in each of the above film layers, the P-type doping can be beryllium, carbon, zinc or a combination thereof, and the doping concentration thereof is, for example, about 10 ¹⁷ cm ^-3 to 10 ¹⁸ cm ^{- 3} (except that the doping concentration of the ohmic contact layer 134 is about 10 ¹⁹ cm ^-3 to 10 ²⁰ cm ^-3 ), and the N-type doping can be doped silicon, and its doping concentration is, for example, about 10 ¹⁷ cm ^-3 to 10 ¹⁸ cm ^-3 , but the new creation is not limited to this. In other embodiments, other appropriate elements can also be doped to achieve P-type doping and N-type doping. In one embodiment, the substrate 160 , the distributed Bragg mirror 110 , and the optical phase control layer 190 are all N-type doped semiconductor layers, and the photonic crystal layer 130 including the cladding layer 132 and the ohmic contact layer 134 are all P-type doped semiconductor layers. Miscellaneous semiconductor layer. Alternatively, in another embodiment, the optical phase control layer 190 and the Bragg mirror 110 may be located on the same side of the active layer 120 as the photonic crystal layer 130 and the ohmic contact layer 134, for example, they may be the same N-type semiconductor layer, or the same P-type semiconductor layer. In addition, in another embodiment, the photonic crystal surface emitting laser 100 may also not include the optical phase control layer 190 , and the active layer 120 directly contacts the distributed Bragg mirror 110 .

In one embodiment, a graded index layer (GRIN layer) may be provided between the distributed Bragg mirror 110 and the substrate 160 , and a refractive index may be provided between the cladding layer 132 and the ohmic contact layer 134 graded layer to reduce the resistance of photonic crystal surface emitting lasers. The graded refractive index layer is a film layer well known to those skilled in the art, so it will not be discussed in detail here, except that when the graded refractive index layer is provided in the photonic crystal layer 130 in this embodiment, the graded refractive index layer There are also a plurality of through holes to communicate with the plurality of through holes of the cladding layer 132 and the ohmic contact layer 134 .

4A is a schematic cross-sectional view of a photonic crystal surface-emitting laser according to another embodiment of the novel creation. Referring to FIG. 4A , the photonic crystal surface-emitting laser 100a of the present embodiment is similar to the photonic crystal surface-emitting laser 100 of FIG. 1 , and the main The difference is described below. In the photonic crystal surface-emitting laser 100a of this embodiment, the photonic crystal layer 130, the optical phase control layer 190a' and the distributed Bragg mirror 110 are located on the same side of the active layer 120. In addition, in this embodiment, the active layer 120 is located between the distributed Bragg mirror 110 and the substrate 160 . In this embodiment, the optical phase control layer 190a' may be disposed on the transparent conductive layer 170, and the distributed Bragg mirror 110 may be disposed on the optical phase control layer 190a'. In addition, the active layer 120 is disposed on the N-type semiconductor layer 190a. The N-type semiconductor layer 190a is disposed on the ohmic contact layer 134a, the ohmic contact layer 134a is disposed on the substrate 160, and the first electrode 140 is disposed on the ohmic contact layer 134a. Alternatively, the ohmic contact layer 134a may also be replaced with another N-type semiconductor layer. In this embodiment, the first electrode 140 and the second electrode 150 are located on the same side of the photonic crystal surface-emitting laser 100a. In another embodiment, the photonic crystal surface-emitting laser 100a may not use the optical phase control layer 190a', but use the N-type semiconductor layer 190a for optical phase control, and the distributed Bragg mirror 110 is disposed on the On the transparent conductive layer 170 and in direct contact with the transparent conductive layer 170 . In this embodiment, since the optical phase control layer 190 a ′ and the distributed Bragg reflector 110 are formed on the transparent conductive layer 170 , the distributed Bragg reflector 110 can use an intermediate material among the above-mentioned materials of the distributed Bragg reflector 110 . The material of the optical phase control layer 190a' can be zinc oxide (ZnO), indium tin oxide (ITO) or other dielectric materials. In addition, in this embodiment, the optical phase control layer 190a' is disposed at the opening 152 of the second electrode 150, and is in contact with the transparent conductive layer 170.

In this embodiment, the substrate 160 may be a transparent substrate, such as a non-conductive substrate A substrate or semi-insulation substrate, which is electrically and transparent to the light 122 emitted by the active layer 120, has a light emitting surface 105, and a portion of the light 122 emitted by the active layer 120 is shown in FIG. 4A. After being reflected by the distributed Bragg mirror 110 located above, the light is emitted from the light emitting surface 105 at the bottom of FIG. 4A .

4B is a schematic cross-sectional view of a photonic crystal surface-emitting laser according to another embodiment of the novel creation. Referring to FIG. 4B , the photonic crystal surface-emitting laser 100c of this embodiment is similar to the photonic crystal surface-emitting laser 100a of FIG. 4A , and the difference between the two lies in the photonic crystal surface-emitting laser of this embodiment. In the emitter 100c, the N-type semiconductor layer 190a is disposed on the substrate 160, which is a conductive substrate, and the first electrode 140 is disposed at the lower edge of the substrate 160, and is electrically connected to the N-type semiconductor layer 190a through the substrate 160.

4C is a schematic cross-sectional view of a photonic crystal surface-emitting laser according to yet another embodiment of the novel creation. Referring to FIG. 4C , the photonic crystal surface-emitting laser 100b of this embodiment is similar to the photonic crystal surface-emitting laser 100 of FIG. 1 , and the main differences between the two are as follows. In the photonic crystal surface-emitting laser 100b of this embodiment, the photonic crystal layer 130c, the optical phase control layer 190 and the distributed Bragg mirror 110 are located on the same side of the active layer 120, and are all N-type semiconductor layers or the same is a P-type semiconductor layer. In addition, on the other side of the active layer 120, a cladding layer 132b without a photonic crystal structure and an ohmic contact layer 134b are sequentially disposed. That is, if the photonic crystal layer 130c, the optical phase control layer 190 and the distributed Bragg mirror 110 are all N-type semiconductor layers, the cladding layer 132b is a P-type semiconductor layer. If the photonic crystal layer 130c, the optical phase control layer 190 and the distributed Bragg mirror 110 are all P-type semiconductor layers, Then the cladding layer 132b is an N-type semiconductor layer. The cladding layer 132b covers the photonic crystal layer 130c and the active layer 120 . Furthermore, the distributed Bragg mirror 110 is disposed on an ohmic contact layer 134 a , and the ohmic contact layer 134 a is disposed on the first electrode 140 .

FIG. 5 is a graph of output light intensity versus input power for sample A and sample B. FIG. Please refer to FIGS. 1 and 5 . Sample B in FIG. 5 is the photonic crystal surface-emitting laser 100 in FIG. 1 , and sample A is similar to sample B, but sample A does not have the distributed Bragg mirror 110 in FIG. 1 . . It can be seen from FIG. 5 that under the same input power, the output light intensity of sample B is about twice that of sample A, which proves that the photonic crystal surface-emitting laser of this embodiment adopts the distributed Bragg mirror 110 The device 100 can indeed effectively improve the utilization rate of light energy.

To sum up, in the photonic crystal surface-emitting laser of the embodiment of the novel creation, the first electrode and the second electrode are used to provide current to make the active layer emit light, and the distributed Bragg reflector is used to The light emitted by the active layer is reflected to one side, so the photonic crystal surface-emitting laser of the embodiment of the present invention has better energy utilization.

100: Photonic crystal surface emitting laser

105: light-emitting surface

110: Distributed Bragg Mirror

120: Active layer

122: Light

130: Photonic crystal layer

131: Through hole

132: Coating

134: Ohmic contact layer

140: First electrode

150: Second electrode

152, 182: Opening

160: Substrate

170: Transparent conductive layer

180: Current limiting layer

190: Optical Phase Control Layer

L: distance

Claims (16)

A photonic crystal surface-emitting laser, comprising: a distributed Bragg reflector; an active layer configured on the distributed Bragg reflector; a photonic crystal layer configured on the distributed Bragg reflector; a first an electrode electrically connected to one side of the active layer; a second electrode electrically connected to the other side of the active layer; and a transparent conductive layer disposed between the active layer and the second electrode, The second electrode is electrically connected to the active layer through the transparent conductive layer, wherein the light emitted by the active layer is reflected by the distributed Bragg reflector, and is transmitted from the opposite side of the photonic crystal surface emitting laser. emerges from a light emitting surface of the distributed Bragg reflector. The photonic crystal surface-emitting laser as claimed in claim 1, wherein a resonance notch wavelength of the light emitted by the active layer between the distributed Bragg reflector and the light exit surface falls on the distributed Bragg reflector The wavelength range corresponding to the plateau region of the reflectance spectrum. The photonic crystal surface-emitting laser according to claim 2, wherein the difference between the photon energy corresponding to the resonance notch wavelength and the photon energy corresponding to the original peak wavelength emitted by the material of the active layer is less than 15meV. The photonic crystal surface-emitting laser according to claim 2, wherein the resonance notch wavelength falls within a wavelength range corresponding to the half width of the luminescence spectrum of the material of the active layer. The photonic crystal surface-emitting laser according to claim 1, further comprising: an optical phase control layer disposed between the distributed Bragg mirror and the active layer, and the thickness of the optical phase control layer is used to control the thickness of the optical phase control layer. The resonance notch wavelength of the light emitted by the active layer between the distributed Bragg mirror and the light exit surface falls within a wavelength range corresponding to the plateau region of the reflection spectrum of the distributed Bragg mirror. The photonic crystal surface-emitting laser according to claim 5, wherein the optical phase control layer is an N-type semiconductor layer, and the photonic crystal layer is a P-type semiconductor layer; or the optical phase control layer is a P-type semiconductor layer , and the photonic crystal layer is an N-type semiconductor layer. The photonic crystal surface-emitting laser according to claim 5, wherein the photonic crystal layer, the optical phase control layer and the distributed Bragg mirror are located on the same side of the active layer. The photonic crystal surface-emitting laser as claimed in claim 7, wherein the photonic crystal layer, the optical phase control layer and the distributed Bragg mirror are both N-type semiconductor layers or P-type semiconductor layers. The photonic crystal surface-emitting laser as claimed in claim 1, further comprising a cladding layer covering the photonic crystal layer and the active layer, wherein the cladding layer is a semiconductor layer. The photonic crystal surface-emitting laser as claimed in claim 1, wherein the transparent conductive layer covers the photonic crystal layer, and is electrically connected to the second electrode and the photonic crystal layer, wherein the light emitting surface is the transparent conductive layer the surface facing away from the distributed Bragg mirror. The photonic crystal surface-emitting laser of claim 10, wherein the second electrode has an opening exposing the light emitting surface. The photonic crystal surface-emitting laser of claim 10, further comprising a current confinement layer disposed between the photonic crystal layer and the transparent conductive layer and having an opening, wherein the transparent conductive layer passes through the opening connected to the photonic crystal layer. The photonic crystal surface-emitting laser of claim 10, wherein the photonic crystal layer comprises: a cladding layer disposed on the active layer; and an ohmic contact layer disposed on the cladding layer and the transparent layer Between the conductive layers and in contact with the transparent conductive layer to form an ohmic contact, wherein the cladding layer and the ohmic contact layer have a photonic crystal structure. The photonic crystal surface-emitting laser of claim 13, wherein the photonic crystal layer has a plurality of through holes located in the cladding layer and the ohmic contact layer, and from the cladding layer to the ohmic contact layer extension to form the photonic crystal structure. The photonic crystal surface-emitting laser according to claim 1, further comprising a substrate disposed between the distributed Bragg mirror and the first electrode. The photonic crystal surface-emitting laser of claim 1, further comprising a substrate, wherein the active layer is located between the distributed Bragg mirror and the substrate.

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