Photoelectric and thermoelectric laser energy collector and preparation method thereof

Abstract

The present invention provides a photoelectric and thermoelectric laser energy harvester and a method for fabricating the same. The photoelectric and thermoelectric laser energy harvester comprises a laser cell, an isolation layer, and a thermoelectric generator. The laser cell comprises a substrate, an epitaxial structure located below the substrate, a groove located in the epitaxial structure, a first electrode layer located at the bottom of the groove, and a second electrode layer located below the epitaxial structure. The epitaxial structure comprises a buffer layer, a first conductivity type heterojunction layer, and a second conductivity type heterojunction layer stacked sequentially downward. The isolation layer is located below the laser cell. The thermoelectric generator comprises a plurality of thermocouples arranged in a columnar structure and spaced apart in sequence, a hot-end conductive interconnect layer, and a cold-end conductive interconnect layer. The present invention converts laser light into electrical energy through a photoelectric conversion layer composed of a first conductivity type heterojunction layer and a second conductivity type heterojunction layer. The thermoelectric generator collects heat transferred from the laser cell, thereby improving the conversion efficiency of laser energy.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated optoelectronics and relates to a photoelectric and thermoelectric laser energy collector and a preparation method thereof. Background Art

[0002] Laser energy transmission is an important wireless energy transmission method with the advantages of strong directionality and concentrated energy. Lasers can carry a large amount of energy and can achieve long-distance power transmission with a relatively low transmission power. It has important practical value in situations where it is difficult to lay wires or the cost of wiring is high. For example, temporary high-altitude unmanned base stations can conveniently charge mobile base stations remotely through laser energy transmission. In addition, the use of laser energy transmission will not interfere with existing wireless communications. At present, laser emission modules in the visible light band have become mature. However, as a core component of laser energy transmission, the development of laser energy collectors is relatively lagging, and laser energy collection in the visible light band is difficult.

[0003] Therefore, there is an urgent need to develop high-performance laser energy harvesters in the visible light band. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a photoelectric and thermoelectric laser energy harvester and a preparation method thereof, so as to solve the problem of difficulty in harvesting laser energy in the visible light band in the prior art.

[0005] To achieve the above-mentioned and other related objectives, the present invention provides a photoelectric and thermoelectric laser energy harvester, comprising:

[0006] A laser cell comprising a substrate, an epitaxial structure located below the substrate, a plurality of spaced grooves located in the epitaxial structure, a first electrode layer located at the bottom of the grooves, and a second electrode layer located below the epitaxial structure, wherein the epitaxial structure comprises a buffer layer, a first conductive type heterojunction layer, and a second conductive type heterojunction layer stacked in sequence downward, and the grooves penetrate the second conductive type heterojunction layer and extend into the first conductive type heterojunction layer;

[0007] an isolation layer, located below the laser cell;

[0008] A thermoelectric generator is located below the isolation layer and includes a hot-end conductive interconnection layer, a cold-end conductive interconnection layer, and a plurality of thermocouples in a columnar structure and arranged in sequence at intervals, wherein the thermocouple includes a first conductive type thermoelectric arm and a second conductive type thermoelectric arm arranged in sequence at intervals, the hot-end conductive interconnection layer electrically connects the top ends of the first conductive type thermoelectric arm and the second conductive type thermoelectric arm in the thermocouple, and the cold-end conductive interconnection layer electrically connects the bottom ends of the first conductive type electric heating arm and the second conductive type electric heating arm adjacent to two adjacent thermocouples.

[0009] Optionally, a surface of the substrate away from the buffer layer is further provided with a plurality of conical structures covering the surface of the substrate, and the surfaces of the conical structures are further provided with an anti-reflection layer covering the surfaces of the conical structures.

[0010] Optionally, the first conductive type heterojunction layer includes a first conductive type GaN layer and a first conductive type InGaN layer stacked sequentially downward, the second conductive type heterojunction layer includes a second conductive type GaN layer and a second conductive type GaN ohmic contact layer stacked sequentially downward, and the first conductive type InGaN layer is located on the upper surface of the second conductive type GaN layer.

[0011] Optionally, the first conductive type GaN layer is exposed at the bottom of the groove.

[0012] Optionally, the laser cell is further provided with a first dielectric layer filling the groove and covering the second electrode layer, a first electrode lead post penetrating the first dielectric layer and electrically connected to the first electrode layer, a second electrode lead post penetrating the first dielectric layer and electrically connected to the second electrode layer, a first electrode interconnection layer located on the lower surface of the first dielectric layer and electrically connected to the first electrode lead post, and a second electrode interconnection layer located on the lower surface of the first dielectric layer and electrically connected to the second electrode lead post, and the first electrode lead post and the second electrode lead post are spaced apart and arranged alternately, and the first electrode interconnection layer and the second electrode interconnection layer are spaced apart and arranged alternately.

[0013] Optionally, the isolation layer covers exposed surfaces of the first dielectric layer, the first electrode interconnection layer, and the second electrode interconnection layer.

[0014] Optionally, the hot end conductive interconnect layer is spaced apart and arranged on the lower surface of the isolation layer.

[0015] Optionally, the first conductive type thermoelectric leg includes a telluride foam porous material, and the second conductive type thermoelectric leg includes a telluride foam porous material.

[0016] Optionally, the photovoltaic and thermoelectric laser energy harvester further includes a heat sink substrate located below the thermoelectric generator.

[0017] Optionally, a second dielectric layer is further provided between the heat sink substrate and the thermoelectric generator, and the second dielectric layer covers the cold end conductive interconnect layer and fixes the thermoelectric generator to the heat sink substrate.

[0018] The present invention also provides a method for preparing a photoelectric and thermoelectric laser energy harvester, comprising the following steps:

[0019] Providing a substrate, the substrate comprising a first surface and a second surface, and forming an epitaxial structure on the first surface of the substrate comprising a buffer layer, a first conductivity type heterojunction layer, and a second conductivity type heterojunction layer stacked in sequence in a direction away from the second surface;

[0020] forming a plurality of grooves spaced at predetermined intervals on a surface of the epitaxial structure away from the first surface, penetrating the second conductive type heterojunction layer and extending to the first conductive type heterojunction layer, and forming a first electrode layer and a second electrode layer at the bottom ends of the grooves and on a surface of the epitaxial structure away from the first surface, respectively, to form a laser cell;

[0021] forming an isolation layer on a side of the laser cell away from the second surface, forming hot end conductive interconnection layers spaced apart from each other on a side of the isolation layer away from the first surface, and forming a thick first photoresist layer covering the isolation layer and the exposed surface of the hot end conductive interconnection layer on a side of the isolation layer away from the first surface;

[0022] Patterning the first photoresist layer to form first through holes spaced at a predetermined distance, forming first conductive type thermoelectric arms in the first through holes, and forming a second photoresist layer on a side of the first photoresist layer away from the first surface to cover the first photoresist layer and the exposed surface of the first conductive type thermoelectric arms;

[0023] The second photoresist layer is patterned to form second through holes spaced apart by a predetermined distance, and second conductive type thermoelectric arms are formed in the second through holes, wherein adjacent first conductive type thermoelectric arms and second conductive type thermoelectric arms form thermocouples, and ends of the thermocouples close to the first surface are electrically connected via the hot end conductive interconnect layer;

[0024] A cold-end conductive interconnection layer is formed on a side of the second photoresist layer away from the first surface to form a thermoelectric generator, and the cold-end conductive interconnection layer electrically connects the first conductive type thermoelectric arm between two adjacent thermocouples and an end of the second conductive type thermoelectric arm away from the first surface.

[0025] Optionally, the first conductive type heterojunction layer includes a first conductive type GaN layer and a first conductive type InGaN layer formed sequentially along a direction away from the substrate; the second conductive type heterojunction layer includes a second conductive type GaN layer and a second conductive type GaN ohmic contact layer formed sequentially along a direction away from the substrate.

[0026] Optionally, after forming the epitaxial structure and before forming the groove, the method further includes forming a conical structure covering the second surface on the second surface of the substrate and forming an anti-reflection layer covering the surface of the conical structure on the surface of the conical structure.

[0027] Optionally, after forming the first electrode layer and the second electrode layer and before forming the isolation layer, the steps also include forming a first dielectric layer filling the groove and covering the second electrode layer, forming a first electrode lead post passing through the first dielectric layer and electrically connected to the first electrode layer, forming a second electrode lead post passing through the first dielectric layer and electrically connected to the second electrode layer, forming a first electrode interconnection layer located on a side of the first dielectric layer away from the first surface and electrically connected to the first electrode lead post, and forming a second electrode interconnection layer spaced a preset distance from the first electrode interconnection layer and electrically connected to the second electrode lead post.

[0028] Optionally, the first electrode lead post and the second electrode lead post are spaced apart by a preset distance, and the isolation layer covers the exposed surfaces of the first dielectric layer, the first electrode interconnection layer and the second electrode interconnection layer.

[0029] Optionally, the first conductive type thermoelectric leg is formed to include a telluride foam porous material; and the second conductive type thermoelectric leg is formed to include a telluride foam porous material.

[0030] Optionally, after forming the cold end conductive interconnect layer, the method further includes forming a second dielectric layer covering the exposed surface of the cold end conductive interconnect layer and fixing the thermoelectric generator to a heat sink substrate through the second dielectric layer.

[0031] As described above, the photoelectric and thermoelectric laser energy collector of the present invention and the preparation method thereof adopt a III-V heterojunction as the photoelectric conversion layer of the laser cell, utilize the diffusion of carriers at the PN junction between the first conductive type heterojunction layer and the second conductive type heterojunction layer to form a built-in electric field, and utilize the difference in band gap width between the first conductive type GaN layer and the first conductive type InGaN layer in the first conductive type heterojunction layer and the difference in band gap width between the second conductive type GaN layer and the second conductive type GaN ohmic contact layer in the second conductive type heterojunction layer to further enhance the built-in electric field, so that the minority carriers of the non-equilibrium carriers injected into both sides of the PN junction between the first conductive type heterojunction layer and the second conductive type heterojunction layer are increased, thereby increasing the open circuit voltage and short circuit current of the laser cell, and utilizing the first conductive type heterojunction layer to further enhance the built-in electric field. A back surface electric field structure is formed at the interface between the first conductive type GaN layer and the first conductive type InGaN layer, and a back surface electric field structure is formed at the interface between the second conductive type GaN layer and the second conductive type GaN ohmic contact layer, so as to facilitate the collection of photogenerated electrons and photogenerated holes, thereby improving the photoelectric conversion efficiency of the laser cell; the incident light energy is converted into electrical energy by the laser cell, and the low-grade thermal energy dissipated during the operation of the laser cell causes the temperature of the top and bottom ends of the thermocouple to be different and generates an electric potential difference between the top and bottom ends of the thermocouple, and then the thermal energy of the thermoelectric generator is collected and converted into electrical energy, thereby improving the laser energy conversion efficiency, and when the laser cell needs to have a stable output, the operating temperature of the laser cell can be regulated by applying a voltage across the thermoelectric generator, which has high industrial utilization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Shown is a schematic cross-sectional structure diagram of the photoelectric and thermoelectric laser energy harvester of the present invention.

[0033] Figure 2 It shows a schematic planar structure diagram of the top surface of the substrate in the photoelectric and thermoelectric laser energy harvester of the present invention.

[0034] Figure 3 It shows a schematic planar structural diagram of the arrangement of the first electrode interconnection layer and the second electrode interconnection layer in the photoelectric thermoelectric laser energy harvester of the present invention.

[0035] Figure 4 It shows a schematic planar structure of the arrangement of the hot-end conductive interconnection layer in the photoelectric thermoelectric laser energy harvester of the present invention.

[0036] Figure 5 It shows a schematic planar structure diagram of the thermocouple arrangement in the photoelectric thermoelectric laser energy harvester according to the present invention.

[0037] Figure 6 It shows a schematic planar structure of the arrangement of the cold-end conductive interconnection layer in the photoelectric and thermoelectric laser energy harvester of the present invention.

[0038] Figure 7 Shown is a process flow chart of the preparation method of the photoelectric and thermoelectric laser energy harvester of the present invention.

[0039] Component number description

[0040] 1 Laser Battery

[0041] 11 substrate

[0042] 111 Conical structure

[0043] 112 Anti-reflective layer

[0044] 12 Epitaxial structure

[0045] 121 buffer layer

[0046] 122 first conductive type heterojunction layer

[0047] 1221 first conductive type GaN layer

[0048] 1222 first conductive type InGaN layer

[0049] 123 Second conductivity type heterojunction layer

[0050] 1231 Second conductivity type GaN layer

[0051] 1232 Second conductivity type GaN ohmic contact layer

[0052] 13 grooves

[0053] 14. First electrode layer

[0054] 141 first electrode lead post

[0055] 15. Second electrode layer

[0056] 151 second electrode lead post

[0057] 16. First dielectric layer

[0058] 17 First electrode interconnection layer

[0059] 18. Second electrode interconnection layer

[0060] 2 Isolation Layer

[0061] 3 Thermoelectric generator

[0062] 31 hot end conductive interconnect layer

[0063] 32 Cold end conductive interconnect layer

[0064] 33 Thermocouple

[0065] 331 first conductive type thermoelectric arm

[0066] 332 Second conductivity type thermoelectric arm

[0067] 4 heat sink substrate

[0068] 41 second dielectric layer DETAILED DESCRIPTION

[0069] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0070] See also Figures 1 to 7 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0071] Example 1

[0072] This embodiment provides a photoelectric and thermoelectric laser energy harvester, such as Figure 1The figure shows a schematic cross-sectional structure of the photoelectric and thermoelectric laser energy harvester, which includes a laser cell 1, an isolation layer 2 and a thermoelectric generator 3, wherein the laser cell includes a substrate 11, an epitaxial structure 12 located below the substrate 1, a plurality of grooves 13 spaced apart in the epitaxial structure 12, a first electrode layer 14 located at the bottom of the grooves 13 and a second electrode layer 15 located below the epitaxial structure 12, the epitaxial structure 12 includes a buffer layer 121, a first conductive type heterojunction layer 122 and a second conductive type heterojunction layer 123 stacked downward in sequence, the groove 13 passes through the second conductive type heterojunction layer 123 and extends into the first conductive type heterojunction layer 122; the isolation layer 2 is located below the laser cell 1; the thermoelectric generator 3 is located below the isolation layer 2, and the thermoelectric generator 3 includes a hot-end conductive interconnection layer 31, a cold-end conductive interconnection layer 32 and a plurality of thermocouples 33 in a columnar structure and arranged in sequence. The thermocouple 33 includes a first conductive type thermoelectric arm 331 and a second conductive type thermoelectric arm 332 arranged in sequence. The hot-end conductive interconnection layer 31 electrically connects the top ends of the first conductive type thermoelectric arm 331 and the second conductive type thermoelectric arm 332 in the thermocouple 33, and the cold-end conductive interconnection layer 32 electrically connects the bottom ends of the first conductive type thermoelectric arm 331 and the second conductive type thermoelectric arm 332 adjacent to each other between two adjacent thermocouples 33.

[0073] Specifically, the substrate 11 is made of sapphire or other suitable transparent materials.

[0074] Specifically, the thickness of the substrate 1 can be set according to actual conditions and is not limited here.

[0075] As an example, Figure 2 As shown, it is a schematic diagram of the planar structure of the side of the substrate 11 away from the buffer layer 121. The side of the substrate 11 away from the buffer layer 12 is also provided with a plurality of conical structures 111 covering the surface of the substrate 1, and the surface of the conical structure 111 is also provided with an anti-reflection layer 112 covering the surface of the conical structure 111.

[0076] Specifically, the size of the tapered structure 111 can be set according to actual conditions and is not limited here.

[0077] Specifically, the tapered structure 111 and the anti-reflection layer 112 covering the tapered structure 111 are used to reduce reflection of incident light and improve absorption efficiency of incident light.

[0078] Specifically, the thickness of the anti-reflection layer 112 can be set according to actual conditions and is not limited here.

[0079] Specifically, the material of the anti-reflection layer 112 includes Al2O3 / SiN x layer or other suitable anti-reflective material.

[0080] Specifically, the first conductivity type includes one of N-type or P-type, the second conductivity type includes one of N-type or P-type, and the first conductivity type is opposite to the second conductivity type. In this embodiment, the first conductivity type is N-type and the second conductivity type is P-type.

[0081] Specifically, the buffer layer 121 is used to alleviate the lattice mismatch between the substrate 1 and the first conductive type heterojunction layer 122 , so as to facilitate the formation of the first conductive type heterojunction layer 122 .

[0082] Specifically, the thickness of the buffer layer 121 can be set according to actual conditions and is not limited here. The buffer layer 121 is made of a non-insulating transparent material.

[0083] Specifically, the operating wavelength band of the laser cell 1 is the visible light band, that is, the wavelength range of 390 nanometers to 780 nanometers.

[0084] Specifically, carriers (electrons and holes) between the first conductive type heterojunction layer 122 and the second conductive type heterojunction layer 123 diffuse into each other, forming a built-in electric field at the PN junction between the first conductive type heterojunction layer 122 and the second conductive type heterojunction layer 123.

[0085] As an example, the first conductive type heterojunction layer 122 includes a first conductive type GaN layer 1221 and a first conductive type InGaN layer 1222 stacked in sequence downward, the second conductive type heterojunction layer 123 includes a second conductive type GaN layer 1231 and a second conductive type GaN ohmic contact layer 1232 stacked in sequence downward, and the first conductive type InGaN layer 1222 is located on the upper surface of the second conductive type GaN layer 1231.

[0086] Specifically, the first conductive type GaN layer 1221 is a heavily doped layer with a wide bandgap, the first conductive type InGaN layer 1222 is a lightly doped layer with a narrow bandgap, and the interface between the first conductive type GaN layer 1221 and the first conductive type InGaN layer 1222 forms a back surface electric field to facilitate the collection of photogenerated electrons; the second conductive type GaN layer 1231 is a heavily doped layer, the doping concentration of the second conductive type GaN ohmic contact layer 1232 is different from the doping concentration of the second conductive type GaN layer 1231, and the second conductive type GaN layer 1231 A back surface electric field structure is formed at the interface with the second conductive type GaN ohmic contact layer 1232 to facilitate the collection of photogenerated holes; the first conductive type InGaN layer 1222 and the second conductive type GaN layer 1231 form a heterojunction, and since the first conductive type InGaN layer 1222 is lightly doped and the second conductive type GaN layer 1231 is heavily doped, the depletion layer of the heterojunction formed by the first conductive type InGaN layer 1222 and the second conductive type GaN layer 1231 is concentrated on the side of the first conductive type InGaN layer 1222.

[0087] Specifically, while ensuring that the second conductive type GaN ohmic contact layer 1232 forms an ohmic contact with the second electrode layer 15 and forms a back surface electric field structure at the interface with the second conductive type GaN layer 1231 that is convenient for collecting photogenerated holes, the doping concentration of the second conductive type GaN ohmic contact layer 1232 can be set according to actual conditions and is no longer restricted here.

[0088] Specifically, the thickness of the first conductive type GaN layer 1221 can be set according to actual conditions and is no longer restricted here; the thickness of the first conductive type InGaN layer 1222 can be set according to actual conditions and is no longer restricted here; the thickness of the second conductive type GaN layer 1231 can be set according to actual conditions and is no longer restricted here; the thickness of the second conductive type GaN ohmic contact layer 1232 can be set according to actual conditions and is no longer restricted here.

[0089] Specifically, the width of the groove 13 can be set based on actual conditions and is not limited here.

[0090] As an example, the first conductive type GaN layer 1221 is exposed at the bottom of the groove 13 , so that the first electrode layer 14 is electrically connected to the first conductive type GaN layer 1221 .

[0091] Specifically, while ensuring that the first conductive type GaN layer 1221 is exposed at the bottom of the groove 13 , the depth of the groove 13 extending in the opposite direction of the stacking direction of the epitaxial structure 12 can be set according to actual conditions and is not limited here.

[0092] Specifically, the thickness of the first electrode layer 14 can be set according to actual conditions and is not limited here.

[0093] Specifically, the material of the first electrode layer 14 includes one of Ti, Al, Ni and Au, and may also be other suitable conductive materials.

[0094] Specifically, the size of the second electrode layer 15 can be set according to actual conditions and is not limited here.

[0095] Specifically, the material of the second electrode layer 15 includes one of Ni and Au, and may also be other suitable conductive materials.

[0096] As an example, the laser cell 1 is further provided with a first dielectric layer 16 filling the groove 13 and covering the second electrode layer 15, a first electrode lead post 141 penetrating the first dielectric layer 16 and electrically connected to the first electrode layer 14, a second electrode lead post 151 penetrating the first dielectric layer 16 and electrically connected to the second electrode layer 15, a first electrode interconnection layer 17 located below the first dielectric layer 16 and electrically connected to the first electrode lead post 141, and a second electrode interconnection layer 18 located below the first dielectric layer 16 and electrically connected to the second electrode lead post 151, and the first electrode lead post 141 and the second electrode lead post 151 are spaced apart and arranged alternately, and the first electrode interconnection layer 17 and the second electrode interconnection layer 18 are spaced apart and arranged alternately.

[0097] Specifically, the material of the first dielectric layer 16 includes one of epoxy resin, silicone, PI, PBO, BCB, silicon oxide, phosphosilicate glass and fluorine-containing glass, and may also be other suitable insulating materials.

[0098] Specifically, the material of the first electrode lead post 141 includes one of Cu, Ni, Ag, Ti, Pt and Au, and may also be other suitable conductive materials.

[0099] Specifically, under the condition that the first electrode lead post 141 passes through the first dielectric layer 16 and is electrically connected to the first electrode layer 14 , the size of the first electrode lead post 141 can be selected according to actual conditions and is not limited here.

[0100] Specifically, the material of the second electrode lead post 151 includes one of Cu, Ni, Ag, Ti, Pt and Au, and may also be other suitable conductive materials.

[0101] Specifically, under the condition that the second electrode lead post 151 passes through the first dielectric layer 16 and is electrically connected to the first electrode layer 15 , the size of the second electrode lead post 151 can be selected according to actual conditions and is not limited here.

[0102] Specifically, the material of the first electrode interconnection layer 17 includes one of Cu, Ni, Ag, Ti, Pt and Au, and may also be other suitable conductive materials.

[0103] Specifically, the thickness of the first electrode interconnection layer 17 can be selected according to actual conditions and is not limited here.

[0104] Specifically, the material of the second electrode interconnection layer 18 includes one of Cu, Ni, Ag, Ti, Pt and Au, and may also be other suitable conductive materials.

[0105] Specifically, the thickness of the second electrode interconnection layer 18 can be selected according to actual conditions and is not limited here. In this embodiment, the first electrode interconnection layer 17 and the second electrode interconnection layer 18 have the same thickness and are made of the same material.

[0106] As an example, Figure 3 , which is a schematic planar structural diagram of the arrangement of the first electrode interconnection layer 17 and the second electrode interconnection layer 18 , wherein the isolation layer 2 covers the exposed surfaces of the first dielectric layer 16 , the first electrode interconnection layer 17 and the second electrode interconnection layer 18 .

[0107] Specifically, the material of the isolation layer 2 includes SiN x Or other suitable insulating materials.

[0108] Specifically, the thickness of the isolation layer 2 can be set according to actual conditions and is not limited here.

[0109] As an example, Figure 4 , which is a schematic planar structural diagram of the arrangement of the hot-end conductive interconnection layer 31 , wherein the hot-end conductive interconnection layer 31 is arranged at intervals on the lower surface of the isolation layer 2 .

[0110] Specifically, the hot-end conductive interconnect layer 31 may be made of one of Cu, Ni, Au, Ag, Al, Ti, Pt, and Sn, or other suitable conductive materials. In this embodiment, an Al layer is used as the hot-end conductive interconnect layer 31 .

[0111] Specifically, the thickness of the hot-end conductive interconnect layer 31 can be selected according to actual conditions and is not limited here.

[0112] Specifically, the spacing distance between two adjacent hot-end conductive interconnect layers 31 can be selected according to actual conditions and is not limited here.

[0113] As an example, Figure 5 Figure 2 shows a schematic planar structure of the arrangement of the thermocouples 33. The first conductive type thermoelectric arm 331 comprises a telluride foam porous material or other suitable first conductive type material. For example, the first conductive type thermoelectric arm 331 may be first conductive type antimony telluride or first conductive type bismuth telluride. The second conductive type thermoelectric arm 332 comprises a telluride foam porous material or other suitable first conductive type material. For example, the second conductive type thermoelectric arm 332 may be second conductive type antimony telluride or second conductive type bismuth telluride. In this embodiment, the first conductive type thermoelectric arm 331 is first conductive type antimony telluride, and the second conductive type thermoelectric arm 332 is second conductive type antimony telluride.

[0114] Specifically, the size of the first conductive type thermoelectric arm 331 can be selected according to actual conditions and is not limited here.

[0115] Specifically, the size of the second conductive type thermoelectric arm 332 can be selected according to actual conditions and is not limited here.

[0116] Specifically, the gap between two adjacent thermocouples 33 and the gap between the first conductive type thermoelectric arm 331 and the second conductive type thermoelectric arm 332 do not need to be filled with a medium. Support is achieved by the first conductive type thermoelectric arm 331 and the second conductive type thermoelectric arm 332 themselves to reduce the parasitic thermal conductivity of the thermoelectric generator 3, thereby improving the thermoelectric conversion efficiency of the device.

[0117] Specifically, the spacing distance between the thermocouples 33 can be set according to actual conditions and is not limited here; the spacing distance between the first conductive type thermoelectric arm 331 and the second conductive type thermoelectric arm 332 can be set according to actual conditions and is not limited here.

[0118] Specifically, such as Figure 6 FIG. 1 is a schematic planar structural diagram of the cold-end conductive interconnect layer 32. The cold-end conductive interconnect layer 32 may be made of one of Cu, Ni, Au, Ag, Al, Ti, Pt, and Sn, or other suitable conductive materials. In this embodiment, an Al layer is used as the cold-end conductive interconnect layer 32.

[0119] Specifically, the thickness of the cold-end conductive interconnect layer 32 can be selected according to actual conditions and is not limited here.

[0120] Specifically, the spacing distance between two adjacent cold-end conductive interconnection layers 32 can be selected according to actual conditions and is not limited here.

[0121] As an example, the photovoltaic and thermoelectric laser energy harvester further includes a heat sink substrate 4 located below the thermoelectric generator 3 .

[0122] Specifically, the heat sink substrate 4 is used to quickly dissipate the heat at the bottom of the thermocouple 33 to prevent heat accumulation at the bottom of the thermocouple 33, reduce the temperature of the end of the thermocouple 33 away from the laser cell 1, increase the temperature difference between the top and bottom of the thermocouple 33, and then improve the thermal energy conversion efficiency of the thermoelectric generator 3.

[0123] Specifically, the heat sink substrate 4 is made of polycrystalline diamond ceramic, SiC ceramic, Si3N4 ceramic, BeO ceramic, AlN ceramic, Ag, Cu, Au, Al or other suitable high thermal conductivity materials. In this embodiment, Cu is used as the material of the heat sink substrate 4.

[0124] Specifically, the thickness of the heat sink substrate 4 can be selected based on actual conditions and is not limited here.

[0125] As an example, a second dielectric layer 41 is further provided between the heat sink substrate 4 and the thermoelectric generator 3 , and the second dielectric layer 41 covers the cold end conductive interconnect layer 32 and fixes the thermoelectric generator 3 to the heat sink substrate 4 .

[0126] Specifically, the second dielectric layer 41 is used to prevent the cold end conductive interconnect layer 32 from being electrically connected to the heat sink substrate 4 .

[0127] Specifically, the second dielectric layer 41 is made of insulating glue or other suitable materials.

[0128] Specifically, the thickness of the second dielectric layer 41 can be selected according to actual conditions and is not limited here.

[0129] Specifically, when the laser in the visible light band of the outside world irradiates the side of the substrate 1 where the conical structure 111 is set, a small part of the laser is lost after passing through the anti-reflection layer 112 and the conical structure 111, and most of the laser passes through the substrate 11 and enters the epitaxial structure 12; when the laser passes through the buffer layer 121 and enters the first conductive type GaN layer 1221, due to the large band gap width of the first conductive type GaN layer 1221, it can only absorb photons with larger energy (i.e., laser with shorter wavelength), and is not absorbed by the first conductive type GaN layer 1221. The laser passes through the first conductive type GaN layer 1221. Since the band gap width of the first conductive type InGaN layer 1222 is narrow, most of the lower energy photons can be absorbed, and then electron-hole pairs are generated at the PN junction between the first conductive type InGaN layer 1222 and the second conductive type GaN layer. The electron-hole pairs are separated into free electrons and holes. Under the action of the built-in electric field, the free electrons move toward the first electrode layer and the holes move toward the second electrode layer 15, forming a photocurrent and generating a certain potential difference at both ends of the laser cell 1.

[0130] Specifically, after the laser in the visible light band is irradiated onto the side of the substrate 1 where the conical structure is set through 111, most of the light energy is directly converted into electrical energy under the action of the laser cell 1; part of the light energy is absorbed by the material of the device and converted into heat energy. At the same time, due to the internal resistance and parasitic resistance of the laser cell 1, part of the electrical energy will be dissipated in the form of heat energy during operation (the heat energy converted from the light energy absorbed by the material of the device and the heat energy generated by the operation of the laser cell are low-grade heat energy). The generated heat energy is conducted to the thermoelectric generator through the isolation layer 2. The top of the thermocouple 33 in the motor 3 is connected to the top of the thermocouple 33, and the heat energy is injected into the thermocouple 33 from the top of the thermocouple 33. After passing through the thermocouple 33, the heat energy is discharged from the heat sink substrate 4 at the bottom of the thermocouple 33, and then a certain temperature distribution is formed on the thermocouple 33. Due to the presence of thermal resistance in the thermocouple 33, a temperature difference is generated between the top and bottom ends of the thermocouple 33. Based on the Seebeck effect, an electric potential proportional to the temperature difference is output at both ends of the thermocouple 33.

[0131] Specifically, when it is necessary to stabilize the output of the laser cell 1, the temperature of the laser cell 1 can be controlled by applying a voltage to the two electrode ends of the thermoelectric generator 3. That is, when the operating temperature of the laser cell 1 needs to be increased, according to the Peltier effect, a voltage is applied to the two electrode ends of the thermoelectric generator 3, so that the current in the first conductive type thermoelectric arm 331 flows from the top to the bottom, and the current in the second conductive type thermoelectric arm 332 flows from the bottom to the top, so that the top of the thermocouple 33 is heated; when the operating temperature of the laser cell 1 needs to be reduced, according to the Peltier effect, a voltage is applied to the two electrode ends of the thermoelectric generator 3, so that the current in the first conductive type thermoelectric arm 331 flows from the bottom to the top, and the current in the second conductive type thermoelectric arm 332 flows from the top to the bottom, so that the top of the thermocouple 33 is cooled.

[0132] The photoelectric and thermoelectric laser energy harvester of this embodiment improves the effective incident efficiency of the laser by forming the conical structure 111 and the anti-reflection film layer on the side of the substrate 11 away from the epitaxial structure 12; the first conductive type heterojunction layer 122 composed of the first conductive type GaN layer 1221 and the first conductive type InGaN layer 1222 and the second conductive type heterojunction layer 123 composed of the second conductive type GaN layer 1231 and the second conductive type GaN ohmic contact layer 1232 are used as the photoelectric conversion layer of the laser cell 1, and the diffusion of carriers at the PN junction between the first conductive type InGaN layer 1222 and the second conductive type GaN layer is used to form a built-in electric field, and the difference in band gap width between the first conductive type GaN layer 1221 and the first conductive type InGaN layer 1222 in the first conductive type heterojunction layer 122 and the first conductive type GaN layer 1231 in the second conductive type heterojunction layer 123 are used to form a built-in electric field. The difference in bandgap width between the first conductive type GaN layer 1221 and the second conductive type InGaN ohmic contact layer 1232 further enhances the built-in electric field, increasing the amount of non-equilibrium minority carriers injected into both sides of the PN junction, thereby increasing the open-circuit voltage and short-circuit current. A back surface electric field structure is formed at the interface between the first conductive type GaN layer 1221 and the first conductive type InGaN layer 1222, and a back surface electric field structure is also formed at the interface between the second conductive type GaN layer 1231 and the second conductive type GaN ohmic contact layer 1232, which is beneficial to the collection of photogenerated electrons and photogenerated holes, thereby improving the photoelectric conversion efficiency of the laser cell 1. The thermoelectric generator 3 is used to collect the heat energy generated by the internal resistance of the laser cell 1 during operation and the heat energy generated by the material in the device after absorbing light energy, and the thermocouple 33 is used to convert the heat energy into electrical energy, thereby improving the conversion efficiency of laser energy. In addition, the thermoelectric generator 3 can be controlled to heat or cool by applying a voltage to the two electrodes of the thermoelectric generator 3, thereby controlling the operating temperature of the laser cell 1.

[0133] Example 2

[0134] This embodiment provides a method for preparing a photoelectric and thermoelectric laser energy harvester. Figure 7 FIG. 1 is a process flow chart of a method for preparing the photoelectric and thermoelectric laser energy harvester, comprising the following steps:

[0135] S1: providing a substrate, the substrate comprising a first surface and a second surface, and forming an epitaxial structure on the first surface of the substrate comprising a buffer layer, a first conductivity type heterojunction layer, and a second conductivity type heterojunction layer stacked in sequence in a direction away from the second surface;

[0136] S2: forming a plurality of grooves spaced apart by a predetermined distance on a surface of the epitaxial structure away from the first surface, penetrating the second conductive type heterojunction layer and extending to the first conductive type heterojunction layer, and forming a first electrode layer and a second electrode layer at the bottom ends of the grooves and on a surface of the epitaxial structure away from the first surface, respectively, to form a laser cell;

[0137] S3: forming an isolation layer on a side of the laser cell away from the second surface, forming a hot end conductive interconnect layer spaced apart from the side of the isolation layer away from the first surface, and forming a thick first photoresist layer covering the isolation layer and the exposed surface of the hot end conductive interconnect layer on the side of the isolation layer away from the first surface;

[0138] S4: patterning the first photoresist layer to form first through holes spaced a predetermined distance apart, forming first conductive type thermoelectric arms in the first through holes, and forming a second photoresist layer on a side of the first photoresist layer away from the first surface to cover the first photoresist layer and the exposed surface of the first conductive type thermoelectric arms;

[0139] S5: patterning the second photoresist layer to form second through holes spaced apart by a preset distance, forming second conductive type thermoelectric arms in the second through holes, and sequentially forming thermocouples with adjacent first conductive type thermoelectric arms and second conductive type thermoelectric arms, with ends of the thermocouples close to the first surface being electrically connected via the hot end conductive interconnect layer;

[0140] S6: forming a cold-end conductive interconnection layer on a side of the second photoresist layer away from the first surface to form a thermoelectric generator, and the cold-end conductive interconnection layer electrically connects the first conductive type thermoelectric arm between two adjacent thermocouples and the end of the second conductive type thermoelectric arm away from the first surface.

[0141] Perform step S1 and step S2: provide a substrate, the substrate including a first surface and a second surface, and form an epitaxial structure on the first surface of the substrate including a buffer layer, a first conductive type heterojunction layer, and a second conductive type heterojunction layer stacked in sequence in a direction away from the second surface; form a plurality of grooves spaced at a preset distance through the second conductive type heterojunction layer and extending to the first conductive type heterojunction layer on a side of the epitaxial structure away from the first surface, and form a first electrode layer and a second electrode layer at the bottom end of the groove and a side of the epitaxial structure away from the first surface, respectively, to form a laser cell.

[0142] Specifically, the buffer layer may be formed by chemical vapor deposition, physical vapor deposition, or other suitable methods. In this embodiment, the buffer layer is formed on the first surface of the substrate by metal organic vapor deposition (MOCVD).

[0143] As an example, the first conductive type heterojunction layer includes a first conductive type GaN layer and a first conductive type InGaN layer formed sequentially along a direction away from the substrate; the second conductive type heterojunction layer includes a second conductive type GaN layer and a second conductive type GaN ohmic contact layer formed sequentially along a direction away from the substrate.

[0144] Specifically, the method for forming the first conductive type GaN layer includes chemical vapor deposition, physical vapor deposition, or other suitable methods; the method for forming the first conductive type InGaN layer includes chemical vapor deposition, physical vapor deposition, or other suitable methods; the method for forming the second conductive type GaN layer includes chemical vapor deposition, physical vapor deposition, or other suitable methods; the method for forming the second conductive type GaN ohmic contact layer includes chemical vapor deposition, physical vapor deposition, or other suitable methods. In this embodiment, the first conductive type GaN layer, the first conductive type InGaN layer, the second conductive type GaN layer, and the second conductive type GaN ohmic contact layer are sequentially formed on the side of the buffer layer facing away from the substrate using a metal organic vapor deposition (MOCVD) method.

[0145] As an example, after forming the epitaxial structure and before forming the groove, the method further includes forming a conical structure covering the second surface on the second surface of the substrate and forming an anti-reflection layer covering the surface of the conical structure on the surface of the conical structure.

[0146] Specifically, the method of forming the tapered structure includes wet etching or other suitable methods.

[0147] Specifically, the method of forming the anti-reflection layer includes one of coating, chemical vapor deposition and physical vapor deposition, and may also be other suitable methods.

[0148] Specifically, forming the groove includes the following steps: forming a third photoresist layer on the side of the epitaxial structure away from the first surface, and patterning the third photoresist layer; etching the epitaxial structure based on the patterned third photoresist layer, stopping etching until the bottom end of the etched groove exposes the first conductive type GaN layer, and removing the third photoresist layer to obtain the groove.

[0149] Specifically, the method for forming the groove includes dry etching and wet etching, or other suitable methods. In this embodiment, inductively coupled plasma (ICP) etching (a type of dry etching) is used to etch the epitaxial structure.

[0150] Specifically, forming the first electrode layer includes the following steps: forming a fourth photoresist layer covering the surface of the epitaxial structure and filling the groove on the side of the epitaxial structure away from the first surface, and patterning the fourth photoresist layer; forming the first electrode layer at the bottom end of the groove based on the patterned fourth photoresist layer.

[0151] Specifically, the method for forming the first electrode layer includes one of chemical vapor deposition, electroplating, physical vapor deposition, evaporation, and magnetron sputtering, and other suitable methods may also be used. In this embodiment, electron beam evaporation (a type of evaporation) is used to form a first electrode material layer on the exposed surface of the patterned fourth photoresist layer and the bottom end of the groove, and then the fourth photoresist layer and the first electrode material layer attached to the surface of the fourth photoresist layer are removed to obtain the first electrode layer.

[0152] Specifically, after forming the groove and before removing the third photoresist layer, a first electrode material layer can be formed on the exposed surface of the third photoresist layer and the bottom of the groove based on the patterned third photoresist layer, and then the third photoresist layer and the first electrode material layer attached to the surface of the third photoresist layer can be removed to obtain the first electrode layer.

[0153] Specifically, forming the second electrode layer includes the following steps: forming a fifth photoresist layer covering the surface of the epitaxial structure and filling the groove on the side of the epitaxial structure away from the first surface, and patterning the fifth photoresist layer; forming the second electrode layer on the exposed surface of the epitaxial structure away from the first surface based on the patterned fifth photoresist layer.

[0154] Specifically, the method for forming the second electrode layer includes chemical vapor deposition, electroplating, physical vapor deposition, evaporation, and magnetron sputtering, and other suitable methods may also be used. In this embodiment, a second electrode material layer is formed on the patterned fifth photoresist layer and the exposed surface of the epitaxial structure away from the first surface using electron beam evaporation. The fifth photoresist layer and the second electrode material layer attached to the surface of the fifth photoresist layer are then removed to obtain the second electrode layer.

[0155] As an example, after forming the first electrode layer and the second electrode layer, before forming the isolation layer, the steps also include forming a first dielectric layer filling the groove and covering the second electrode layer, forming a first electrode lead post passing through the first dielectric layer and electrically connected to the first electrode layer, forming a second electrode lead post passing through the first dielectric layer and electrically connected to the second electrode layer, forming a first electrode interconnection layer located on a side of the first dielectric layer away from the first surface and electrically connected to the first electrode lead post, and forming a second electrode interconnection layer spaced a preset distance from the first electrode interconnection layer and electrically connected to the second electrode lead post.

[0156] Specifically, the method for forming the first dielectric layer includes at least one of chemical vapor deposition, physical vapor deposition, and high-temperature reflow, and other suitable methods may also be used. In this embodiment, chemical vapor deposition is used to form a phosphosilicate glass layer on a side of the epitaxial structure away from the first surface, and high-temperature reflow is used to form a planarized first dielectric layer.

[0157] As an example, the first electrode lead post is spaced apart from the second electrode lead post by a preset distance.

[0158] Specifically, forming the first electrode lead post includes the following steps: forming a sixth photoresist layer on a side of the first dielectric layer away from the first surface, and patterning the sixth photoresist layer; forming a first opening that penetrates the first dielectric layer and exposes the first electrode layer and a second opening that penetrates the first dielectric layer and exposes the second electrode layer based on the patterned four photoresist layers; forming a first electrode lead post filling the first opening in the first opening, forming a second electrode lead post filling the second opening in the second opening, and removing the sixth photoresist layer.

[0159] Specifically, the method for forming the first opening includes one of wet etching or dry etching, or other suitable methods; the method for forming the first electrode lead column includes one of chemical vapor deposition, electroplating, physical vapor deposition, evaporation and magnetron sputtering, or other suitable methods.

[0160] Specifically, the method for forming the second opening includes one of wet etching or dry etching, or other suitable methods; the method for forming the second electrode lead column includes one of chemical vapor deposition, electroplating, physical vapor deposition, evaporation and magnetron sputtering, or other suitable methods.

[0161] Specifically, the first opening and the first electrode lead post may be formed by using the sixth photoresist layer, and after removing the sixth photoresist layer, the second opening and the second electrode lead post may be formed by using the same method.

[0162] Specifically, forming the first electrode interconnection layer includes the following steps: forming a fifth photoresist layer on the side of the first dielectric layer away from the substrate, and patterning the fifth photoresist layer; forming the first electrode interconnection layer and the second electrode interconnection layer based on the patterned fifth photoresist layer, and removing the fifth photoresist layer.

[0163] Specifically, the first electrode interconnect layer may be formed by chemical vapor deposition, electroplating, physical vapor deposition, evaporation, and magnetron sputtering, or by other suitable methods. The second electrode interconnect layer may be formed by chemical vapor deposition, electroplating, physical vapor deposition, evaporation, and magnetron sputtering, or by other suitable methods. In this embodiment, the first and second electrode interconnect layers are formed simultaneously using electron beam evaporation.

[0164] Specifically, the first electrode interconnection layer may be formed by using the seventh photoresist layer, and after removing the fifth photoresist layer, the second electrode interconnection layer may be formed by using the same method.

[0165] Execute step S3: form an isolation layer on a side of the laser cell away from the second surface, form a hot end conductive interconnect layer spaced apart on a side of the isolation layer away from the first surface, and form a thick first photoresist layer covering the isolation layer and the exposed surface of the hot end conductive interconnect layer on a side of the isolation layer away from the first surface.

[0166] Specifically, the method of forming the isolation layer includes one of chemical vapor deposition and physical vapor deposition, or other suitable methods.

[0167] As an example, the isolation layer covers exposed surfaces of the first dielectric layer, the first electrode interconnection layer, and the second electrode interconnection layer.

[0168] Specifically, forming the hot end conductive interconnect layer includes the following steps: forming an eighth photoresist layer on a side of the isolation layer away from the substrate, and patterning the eighth photoresist layer; and forming the hot end conductive interconnect layer based on the patterned eighth photoresist layer.

[0169] Specifically, the hot-end conductive interconnect layer is formed by one of chemical vapor deposition, electroplating, physical vapor deposition, evaporation, and magnetron sputtering, or other suitable methods. In this embodiment, the hot-end conductive interconnect layer is formed by electron beam evaporation.

[0170] Execute step S4 and step S5: pattern the first photoresist layer to form first through holes spaced at a preset distance, form a first conductive type thermoelectric arm in the first through hole, and form a second photoresist layer covering the first photoresist layer and the exposed surface of the first conductive type thermoelectric arm on a side of the first photoresist layer away from the first surface; pattern the second photoresist layer to form second through holes spaced at a preset distance, form a second conductive type thermoelectric arm in the second through hole, and the first conductive type thermoelectric arm and the second conductive type thermoelectric arm adjacent to each other in sequence form a thermocouple, and the end of the thermocouple close to the first surface is electrically connected through the hot end conductive interconnect layer.

[0171] As an example, the first conductive type thermoelectric leg is formed to include a telluride foam porous material; and the second conductive type thermoelectric leg is formed to include a telluride foam porous material.

[0172] Specifically, forming the first conductivity type thermoelectric leg further includes the steps of filling the first through-hole with a first conductivity type telluride gel and drying the first conductivity type telluride gel. In this embodiment, the first through-hole is filled with a first conductivity type doped antimony telluride or bismuth telluride gel, and the first conductivity type doped antimony telluride or bismuth telluride gel filling the first through-hole is dried to obtain a porous foamed first conductivity type thermoelectric leg.

[0173] Specifically, the porous foam of the first conductive type thermoelectric arm is formed to enhance the thermal resistance of the first conductive type thermoelectric arm, thereby reducing the diffusion speed of heat in the first conductive type thermoelectric arm and enhancing the temperature difference between the top and bottom ends of the thermocouple.

[0174] Specifically, forming the second conductivity type thermoelectric leg further includes the steps of filling the second through hole with a second conductivity type telluride gel and drying the second conductivity type telluride gel. In this embodiment, the second through hole is filled with a second conductivity type doped antimony telluride or bismuth telluride gel, and the second conductivity type doped antimony telluride or bismuth telluride gel filling the second through hole is dried to obtain a porous foamed second conductivity type thermoelectric leg.

[0175] Specifically, the second conductive type thermoelectric arm is formed into a porous foam to enhance the thermal resistance of the second conductive type thermoelectric arm, thereby reducing the diffusion speed of heat in the second conductive type thermoelectric arm and enhancing the temperature difference between the top and bottom ends of the thermocouple.

[0176] Specifically, the thickness of the first photoresist layer can be selected according to the required height of the first conductive type thermoelectric arm, which is not limited here.

[0177] Specifically, the method of forming the first photoresist layer and the method of forming the second photoresist layer are conventional methods and are not limited here.

[0178] Specifically, after forming the second conductive type thermoelectric arm, the second photoresist layer is removed, and the first photoresist layer is retained.

[0179] Perform step S6: forming a cold-end conductive interconnection layer on a side of the second photoresist layer away from the first surface to form a thermoelectric generator, and the cold-end conductive interconnection layer electrically connects the first conductive type thermoelectric arm between two adjacent thermocouples and the end of the second conductive type thermoelectric arm away from the first surface.

[0180] Specifically, forming the cold-end conductive interconnect layer includes the following steps: forming a ninth photoresist layer on the side of the first photoresist layer away from the substrate, and patterning the ninth photoresist layer; and forming the cold-end conductive interconnect layer based on the patterned ninth photoresist layer to electrically connect the bottom ends of the first conductive type thermoelectric arm and the second conductive type thermoelectric arm between two adjacent thermocouples.

[0181] Specifically, the cold end conductive interconnect layer is formed by one of chemical vapor deposition, electroplating, physical vapor deposition, evaporation, and magnetron sputtering, or other suitable methods. In this embodiment, the cold end conductive interconnect layer is formed by electron beam evaporation.

[0182] Specifically, after forming the cold-end conductive interconnect layer, the first photoresist layer and the ninth photoresist layer are removed to obtain the thermoelectric generator.

[0183] As an example, after forming the cold end conductive interconnect layer, the method further includes forming a second dielectric layer covering the exposed surface of the cold end conductive interconnect layer and fixing the thermoelectric generator to a heat sink substrate through the second dielectric layer.

[0184] Specifically, the second dielectric layer can be formed by coating or other suitable methods. In this embodiment, the second dielectric layer is formed on one side of the heat sink substrate by coating, and the end of the thermoelectric generator facing away from the substrate is bonded to the second dielectric layer to secure the thermoelectric generator to the thermal deposition substrate.

[0185] The preparation method of the photoelectric thermoelectric laser energy collector of this embodiment utilizes the first conductive type heterojunction layer and the second conductive type heterojunction layer to convert visible laser energy into electrical energy, utilizes the first conductive type thermoelectric arm and the second conductive type thermoelectric arm composed of telluride to convert the heat transferred from the laser cell into electrical energy, and dissipates the heat converted into electrical energy through the heat sink substrate, thereby improving the conversion efficiency of laser into electrical energy, and the preparation process is simple.

[0186] In summary, the photoelectric thermoelectric laser energy harvester and its preparation method of the present invention convert visible laser energy into electrical energy by utilizing a first conductive type heterojunction layer including a first conductive type GaN layer and a first conductive type InGaN layer and a second conductive type heterojunction layer including a second conductive type GaN and a second conductive type GaN ohmic contact layer to form a photoelectric conversion layer, and utilize the difference in band gap width between the first conductive type GaN layer and the first conductive type InGaN layer and the difference in band gap width between the second conductive type GaN layer and the second conductive type GaN ohmic contact layer to enhance the strength of the built-in electric field between the first conductive type heterojunction layer and the second conductive type heterojunction layer, thereby increasing the number of minority carriers injected into the non-equilibrium carriers on both sides of the PN junction between the first conductive type heterojunction layer and the second conductive type heterojunction layer, thereby increasing the open circuit of the laser cell. Voltage and short-circuit current; utilizing the difference in doping concentration between the first conductivity type GaN layer and the first conductivity type InGaN layer, as compared to the interface between the first conductivity type GaN layer and the first conductivity type InGaN layer, to form a back surface electric field structure to facilitate the collection of photogenerated electrons; utilizing the difference in doping concentration between the second conductivity type GaN layer and the second conductivity type GaN ohmic contact layer, as compared to the second conductivity type heterojunction layer, to form a back surface electric field structure to facilitate the collection of photogenerated holes, thereby enhancing the photoelectric conversion efficiency of the laser cell; utilizing a thermoelectric generator to collect heat generated by the operation of the laser cell and heat generated by the laser cell material absorbing the laser light, resulting in a temperature difference between the top and bottom ends of the thermocouple in the thermoelectric generator due to the different heat distribution, thereby generating a potential difference between the top and bottom ends of the thermocouple, thereby converting thermal energy into electrical energy and improving the laser energy conversion efficiency. In addition, when the laser cell requires a specified operating temperature, a voltage is applied to the two electrodes of the thermoelectric generator, and the direction of the current in the thermocouple is controlled to control the heating or cooling of the thermocouple, thereby regulating the operating temperature of the laser cell. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0187] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A photoelectric and thermoelectric laser energy harvester, characterized in that: include: A laser cell, comprising a substrate, an epitaxial structure located below the substrate, a plurality of grooves spaced apart in the epitaxial structure, a first electrode layer located at the bottom of the grooves, and a second electrode layer located below the epitaxial structure, wherein the epitaxial structure comprises a buffer layer, a first conductivity type heterojunction layer, and a second conductivity type heterojunction layer stacked sequentially downward, the grooves penetrate the second conductivity type heterojunction layer and extend into the first conductivity type heterojunction layer, the first conductivity type heterojunction layer comprises a first conductivity type GaN layer and a first conductivity type InGaN layer stacked sequentially downward, the second conductivity type heterojunction layer comprises a second conductivity type GaN layer and a second conductivity type GaN ohmic contact layer stacked sequentially downward, and the first conductivity type InGaN layer is located on an upper surface of the second conductivity type GaN layer; an isolation layer, located below the laser cell; A thermoelectric generator is located below the isolation layer and includes a hot-end conductive interconnection layer, a cold-end conductive interconnection layer, and a plurality of thermocouples in a columnar structure and arranged in sequence at intervals, wherein the thermocouple includes a first conductive type thermoelectric arm and a second conductive type thermoelectric arm arranged in sequence at intervals, the hot-end conductive interconnection layer electrically connects the top ends of the first conductive type thermoelectric arm and the second conductive type thermoelectric arm in the thermocouple, and the cold-end conductive interconnection layer electrically connects the bottom ends of the first conductive type thermoelectric arm and the second conductive type thermoelectric arm adjacent to two adjacent thermocouples.

2. The photoelectric and thermoelectric laser energy harvester according to claim 1, characterized in that: A surface of the substrate away from the buffer layer is further provided with a plurality of cone structures covering the surface of the substrate, and the surface of the cone structure is further provided with an anti-reflection layer covering the surface of the cone structure.

3. The photoelectric and thermoelectric laser energy harvester according to claim 1, characterized in that: The first conductive type GaN layer is exposed at the bottom of the groove.

4. The photoelectric and thermoelectric laser energy harvester according to claim 1, characterized in that: The laser cell is also provided with a first dielectric layer filling the groove and covering the second electrode layer, a first electrode lead post penetrating the first dielectric layer and electrically connected to the first electrode layer, a second electrode lead post penetrating the first dielectric layer and electrically connected to the second electrode layer, a first electrode interconnection layer located on the lower surface of the first dielectric layer and electrically connected to the first electrode lead post, and a second electrode interconnection layer located on the lower surface of the first dielectric layer and electrically connected to the second electrode lead post, and the first electrode lead post and the second electrode lead post are spaced apart and arranged alternately, and the first electrode interconnection layer and the second electrode interconnection layer are spaced apart and arranged alternately.

5. The photoelectric and thermoelectric laser energy harvester according to claim 4, characterized in that: The isolation layer covers the exposed surfaces of the first dielectric layer, the first electrode interconnection layer, and the second electrode interconnection layer.

6. The photoelectric and thermoelectric laser energy harvester according to claim 1, characterized in that: The hot end conductive interconnection layer is spaced apart and arranged on the lower surface of the isolation layer.

7. The photoelectric and thermoelectric laser energy harvester according to claim 1, characterized in that: The first conductive type thermoelectric leg includes a telluride foam porous material, and the second conductive type thermoelectric leg includes a telluride foam porous material.

8. The photoelectric and thermoelectric laser energy harvester according to claim 1, characterized in that: The photovoltaic and thermoelectric laser energy collector further includes a heat sink substrate located below the thermoelectric generator.

9. The photoelectric and thermoelectric laser energy harvester according to claim 8, characterized in that: A second dielectric layer is further provided between the heat sink substrate and the thermoelectric generator, and the second dielectric layer covers the cold end conductive interconnect layer and fixes the thermoelectric generator to the heat sink substrate.

10. A method for preparing a photoelectric and thermoelectric laser energy harvester, characterized in that: The following steps are involved: Providing a substrate, the substrate comprising a first surface and a second surface, and forming an epitaxial structure on the first surface of the substrate comprising a buffer layer, a first conductivity type heterojunction layer, and a second conductivity type heterojunction layer stacked in sequence in a direction away from the second surface; forming a plurality of grooves spaced at predetermined intervals on a surface of the epitaxial structure away from the first surface, penetrating the second conductive type heterojunction layer and extending to the first conductive type heterojunction layer, and forming a first electrode layer and a second electrode layer at the bottom ends of the grooves and on a surface of the epitaxial structure away from the first surface, respectively, to form a laser cell; forming an isolation layer on a side of the laser cell away from the second surface, forming hot end conductive interconnection layers spaced apart from each other on a side of the isolation layer away from the first surface, and forming a thick first photoresist layer covering the isolation layer and the exposed surface of the hot end conductive interconnection layer on a side of the isolation layer away from the first surface; Patterning the first photoresist layer to form first through holes spaced at a predetermined distance, forming first conductive type thermoelectric arms in the first through holes, and forming a second photoresist layer on a side of the first photoresist layer away from the first surface to cover the first photoresist layer and the exposed surface of the first conductive type thermoelectric arms; The second photoresist layer is patterned to form second through holes spaced apart by a predetermined distance, and second conductive type thermoelectric arms are formed in the second through holes, wherein adjacent first conductive type thermoelectric arms and second conductive type thermoelectric arms form thermocouples, and ends of the thermocouples close to the first surface are electrically connected via the hot end conductive interconnect layer; A cold-end conductive interconnection layer is formed on a side of the second photoresist layer away from the first surface to form a thermoelectric generator, and the cold-end conductive interconnection layer electrically connects the first conductive type thermoelectric arm between two adjacent thermocouples and an end of the second conductive type thermoelectric arm away from the first surface.

11. The method for preparing a photoelectric and thermoelectric laser energy harvester according to claim 10, characterized in that: The first conductive type heterojunction layer includes a first conductive type GaN layer and a first conductive type InGaN layer formed in sequence along a direction away from the substrate; the second conductive type heterojunction layer includes a second conductive type GaN layer and a second conductive type GaN ohmic contact layer formed in sequence along a direction away from the substrate.

12. The method for preparing the photoelectric and thermoelectric laser energy harvester according to claim 10, characterized in that: After forming the epitaxial structure and before forming the groove, the method further includes forming a conical structure covering the second surface on the second surface of the substrate and forming an anti-reflection layer covering the surface of the conical structure.

13. The method for preparing a photoelectric and thermoelectric laser energy harvester according to claim 10, characterized in that: After forming the first electrode layer and the second electrode layer, and before forming the isolation layer, the method also includes forming a first dielectric layer filling the groove and covering the second electrode layer, forming a first electrode lead post penetrating the first dielectric layer and electrically connected to the first electrode layer, forming a second electrode lead post penetrating the first dielectric layer and electrically connected to the second electrode layer, forming a first electrode interconnection layer located on a side of the first dielectric layer away from the first surface and electrically connected to the first electrode lead post, and forming a second electrode interconnection layer spaced a preset distance from the first electrode interconnection layer and electrically connected to the second electrode lead post.

14. The method for preparing a photoelectric and thermoelectric laser energy harvester according to claim 13, wherein: The first electrode lead post is spaced apart from the second electrode lead post by a preset distance, and the isolation layer covers the exposed surfaces of the first dielectric layer, the first electrode interconnection layer, and the second electrode interconnection layer.

15. The method for preparing a photoelectric and thermoelectric laser energy harvester according to claim 10, characterized in that: The first conductive type thermoelectric leg is formed to include a telluride foam porous material; and the second conductive type thermoelectric leg is formed to include a telluride foam porous material.

16. The method for preparing a photoelectric and thermoelectric laser energy harvester according to claim 10, characterized in that: After forming the cold end conductive interconnection layer, the method further includes forming a second dielectric layer covering the exposed surface of the cold end conductive interconnection layer and fixing the thermoelectric generator to a heat sink substrate through the second dielectric layer.

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