A Gallium Nitride Microwire Array Photodetector and Its Preparation Method

Abstract

The present invention discloses a gallium nitride micro-wire array photodetector and a preparation method thereof. The photodetector includes: a silicon substrate, a methylammonium lead iodide layer, and an electrode; a plurality of grooves arranged in parallel are formed on the upper surface of the silicon substrate; an insulating layer covers the surface of the protruding portion on the upper surface of the silicon substrate; gallium nitride micro-wires are epitaxially grown on the two inner sidewalls of the grooves respectively, the extending direction of the gallium nitride micro-wires is the same as the extending direction of the grooves, and the gallium nitride micro-wires form a parallel micro-wire array; the electrode is disposed on the upper surface of the silicon substrate, and the methylammonium lead iodide layer is coated on the upper surface of the silicon substrate to cover the electrode and the gallium nitride micro-wires so as to form a double heterojunction. The photodetector has low dark current, fast response speed, high on / off current ratio, and long detection range, with good comprehensive performance, and the device structure is simple and easy to manufacture.

Description

Technical Field

[0001] The present invention relates to the technical field of photodetectors, and particularly to a gallium nitride micro-wire array photodetector and a preparation method thereof. Background Art

[0002] The working principle of a photodetector is to convert an optical signal into an electrical signal. A photodetector is an important part of the field of optoelectronic information technology and has a wide range of applications in military, medical, and daily life. For example: spacecraft, missile launch, fire detection, and video imaging, etc. As a member of wide-bandgap semiconductors, gallium nitride (GaN) is considered an ideal material for making detectors due to its wide bandgap (bandgap width 3.4 eV), low dielectric constant, high temperature resistance, corrosion resistance, radiation resistance, etc. With the continuous development and progress of science, materials are increasingly developing towards low dimensions and small sizes. Among one-dimensional nanostructures, micro / nano-wires have better crystal quality and a larger surface area compared to bulk materials. Thus, many gallium nitride micro / nano-wire structure photodetectors have emerged.

[0003] Gallium nitride photodetectors can be divided into photoconductive type and photovoltaic type due to different working principles. The photovoltaic type can be further divided into Schottky type and homo / heterojunction type. Photoconductive detectors have high gain but large dark current, and Schottky type has fast response speed but is greatly affected by the potential barrier. Therefore, in order to obtain both a fast response speed and a low dark current, the heterojunction type is the best choice. Due to the booming development of perovskite materials in recent years, perovskite materials have good binding properties and good material characteristics, and are a better choice as another material for heterojunctions. Organic-inorganic hybrid perovskites have better stability, longer diffusion length, and adjustable bandgap compared to pure organic or pure inorganic perovskites. As a representative, methylammonium lead iodide (CH3NH3PbI3) has a low bandgap width (1.53 eV) and a high absorption coefficient in the visible and near-infrared regions. Therefore, using CH3NH3PbI3 and n-type GaN to form an ultraviolet-visible-near-infrared photodetector is an ideal choice.

[0004] Nowadays, some domestic and foreign teams and individuals have conducted some research on CH3NH3PbI3 / GaN photodetectors, but most of them are combinations of GaN thin films and CH3NH3PbI3. These photodetectors still have the following defects: large dark current, low response speed, and complex preparation; their comprehensive performance still needs to be further improved. Summary of the Invention

[0005] To overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a gallium nitride micro-wire array photodetector, which has low dark current, fast response speed, high on / off current ratio, long detection range, good comprehensive performance, and a simple device structure that is easy to manufacture.

[0006] Another objective of the present invention is to provide a method for preparing a gallium nitride micro-wire array photodetector, and the prepared photodetector has low dark current, fast response speed, high on / off current ratio, long detection range, and a simple device structure.

[0007] One of the objectives of the present invention is achieved by the following technical solutions:

[0008] A gallium nitride micro-wire array photodetector includes: a silicon substrate, a methylammonium lead iodide layer, and electrodes; a plurality of parallel grooves are formed on the upper surface of the silicon substrate; an insulating layer covers the surface of the protruding portion on the upper surface of the silicon substrate; gallium nitride micro-wires are epitaxially grown on the two inner sidewalls of the grooves respectively, the extending direction of the gallium nitride micro-wires is the same as the extending direction of the grooves, and the gallium nitride micro-wires form a parallel micro-wire array; the electrodes are disposed on the upper surface of the silicon substrate, and the methylammonium lead iodide layer is coated on the upper surface of the silicon substrate to cover the electrodes and the gallium nitride micro-wires to form a double heterojunction.

[0009] Further, an aluminum nitride buffer layer is provided between the gallium nitride micro-wires and the inner sidewalls of the grooves.

[0010] Further, the thickness of the aluminum nitride buffer layer is 30 to 300 nm.

[0011] Further, the width of the grooves is 8 to 12 μm, and the depth of the grooves is 2.5 to 4 μm.

[0012] Further, the thickness of the methylammonium lead iodide layer is 200 to 400 nm.

[0013] Another objective of the present invention is achieved by the following technical solutions:

[0014] A method for preparing a gallium nitride micro-wire array photodetector includes the following steps:

[0015] Etching a plurality of equally spaced grooves on the upper surface of a silicon substrate covered with an insulating layer;

[0016] Epitaxially growing gallium nitride micro-wires on the two inner sidewalls of the grooves to form a micro-wire array, and the extending direction of the gallium nitride micro-wires is the same as the extending direction of the grooves;

[0017] After growing the gallium nitride micro-wires, depositing electrodes on the upper surface of the silicon substrate;

[0018] After depositing the electrodes, a layer of lead methylammonium iodide is coated on the upper surface of the silicon substrate to cover the electrodes and the gallium nitride micro-wires, thereby forming a double heterojunction.

[0019] Further, before growing the gallium nitride micro-wires, the steps also include: epitaxially growing a layer of aluminum nitride buffer layer on the inner sidewall of the groove by metal-organic chemical vapor deposition; epitaxially growing the gallium nitride micro-wires on the aluminum nitride buffer layer.

[0020] Further, the etching of a plurality of equally-spaced grooves on the upper surface of the silicon substrate covered with an insulating layer specifically is:

[0021] Preparing an insulating material on the front surface of the clean silicon substrate to form an insulating layer;

[0022] Spin-coating a photoresist on the surface of the insulating layer, and through pre-baking, exposure, post-baking, and developing, a periodically arranged strip-shaped epitaxial pattern is exposed on the surface of the insulating layer;

[0023] Selectively etching the upper surface of the silicon substrate according to the strip-shaped epitaxial pattern, and then performing a de-gluing treatment on the silicon substrate;

[0024] According to the required groove depth, after de-gluing, the part of the silicon substrate not covered with the insulating layer is etched by timed wet etching to form a plurality of equally-spaced parallel grooves.

[0025] Further, the deposition of the electrodes on the upper surface of the silicon substrate specifically is: evaporating or sputtering Au on the side of the silicon substrate where the gallium nitride micro-wires are provided by thermal evaporation or ion sputtering to form a metal electrode.

[0026] Further, the coating of the layer of lead methylammonium iodide on the upper surface of the silicon substrate specifically is: spin-coating the layer of lead methylammonium iodide on the upper surface of the silicon substrate in a glove box.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This photodetector adopts the method of growing micro-wires in the grooves. Growing micro-wires in the grooves can greatly utilize the limited area of the substrate, making the surface-to-volume ratio maximized, greatly reducing the defects caused by lattice mismatch and thermal mismatch, and having a very high crystal quality. At the same time, the contact area of the heterojunction is increased, making it have a large space charge region, enabling effective separation of photo-generated carriers, effectively suppressing the recombination of photo-generated carriers, and improving the detector response speed. This photodetector has low dark current, fast response speed, high on / off current ratio, and long detection range, with good comprehensive performance, and the device structure is simple and easy to manufacture. Description of the Drawings

[0029] Figure 1 Schematic structural diagram of a gallium nitride micro-wire array photodetector provided by the present invention;

[0030] Figure 2 Schematic structural diagram of the substrate of a gallium nitride micro-wire array photodetector provided by the present invention when no gallium nitride micro-wires are grown;

[0031] Figure 3 Schematic structural diagram of the substrate of a gallium nitride micro-wire array photodetector provided by the present invention on which gallium nitride micro-wires are epitaxially grown;

[0032] Figure 4 is Figure 3 Cross-sectional schematic diagram of the substrate in

[0033] Figure 5 is Figure 1 Cross-sectional schematic diagram of the photodetector in at the electrode position;

[0034] Figure 6 is Figure 1 Cross-sectional schematic diagram of the photodetector in at a non-electrode position, showing the double heterojunction structure formed by the photodetector;

[0035] Figure 7 is Figure 1 Cross-sectional schematic diagram of the photodetector in taken along the extension direction of the groove at the position of the groove side wall;

[0036] Figure 8 I-V diagram of a gallium nitride micro-wire array photodetector provided by the present invention under illumination with different optical powers at 325 nm;

[0037] Figure 9 I-T (partial) of a gallium nitride micro-wire array photodetector provided by the present invention under illumination with a 5 V applied voltage, 325 nm, and 7.5 mw / cm2;

[0038] Figure 10 I-V diagram of a gallium nitride micro-wire array photodetector provided by the present invention under illumination with different optical powers at 532 nm;

[0039] Figure 11 I-T (partial) of a gallium nitride micro-wire array photodetector provided by the present invention under illumination with a 5 V applied voltage, 532 nm, and 27.4 mw / cm2;

[0040] Figure 12 I-V diagram of a gallium nitride micro-wire array photodetector provided by the present invention under illumination with different optical powers at 750 nm;

[0041] Figure 13 I-T (partial) of a gallium nitride microwire array photodetector provided by the present invention under an externally applied voltage of 5V, light irradiation at 750nm, and 0.3mw / cm2.

[0042] In the figure: 10, silicon substrate; 101, groove; 102, insulating layer; 20, methylammonium lead iodide layer; 30, electrode; 40, gallium nitride microwire; 50, aluminum nitride buffer layer. Detailed implementation manners

[0043] Next, in combination with the accompanying drawings and specific implementation manners, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0044] Please refer to Figures 1 to 7 , a gallium nitride microwire array photodetector, comprising: a silicon substrate 10, a methylammonium lead iodide layer 20, and an electrode 30; the silicon substrate 10 is a high-resistance silicon wafer (resistivity > 10 5 Ω·cm), and the crystal orientation of the silicon wafer is <100>; a plurality of parallel grooves 101 are formed on the upper surface of the silicon substrate 10; the surface of the convex part on the upper surface of the silicon substrate 10 is covered with an insulating layer 102; the resistivity of the insulating layer 102 is greater than 10 16 Ω·cm; the insulating layer 102 is made of silicon dioxide; the thickness of the insulating layer 102 is preferably 300 - 500nm; gallium nitride microwires 40 are epitaxially grown on the two inner sidewalls of the groove 101 respectively, the extending direction of the gallium nitride microwires 40 is the same as the extending direction of the groove 101, and the gallium nitride microwires 40 form a parallel microwire array; the electrode 30 is a metal electrode, the electrode 30 is arranged on the upper surface of the silicon substrate 10, that is, above the gallium nitride microwire array, and the methylammonium lead iodide layer 20 is coated on the upper surface of the silicon substrate 10 to cover the electrode 30 and the gallium nitride microwires 40 to form a double heterojunction, that is, the methylammonium lead iodide layer 20 and the gallium nitride microwire array form a double heterojunction.

[0045] The photodetector etches a groove 101 on a substrate, and then grows microwires in the groove 101. Growing microwires in the groove 101 can make great use of the limited area of the substrate, maximize the surface area ratio, and due to the growth in the restricted area within the groove 101, defects caused by lattice mismatch and thermal mismatch due to the stacking between layers in a film-like structure are greatly reduced, and it has a high crystal quality. At the same time, the contact area of the heterojunction is increased, making it have a large space charge region, effectively separating photo-generated carriers, effectively suppressing the recombination of photo-generated carriers, and improving the detector response speed. The photodetector has a low dark current, a fast response speed, a high on / off current ratio, and a long detection range, with good comprehensive performance, and the device structure is simple and easy to manufacture.

[0046] The working process of the photodetector is as follows: The methylammonium lead iodide layer 20 absorbs light radiation to generate photo-generated carriers; electrons and holes are rapidly separated in the space charge region formed between the methylammonium lead iodide and the gallium nitride microwire array; holes remain in the methylammonium lead iodide layer 20, while electrons move towards the gallium nitride microwires 40; and finally are collected at the metal electrode 30.

[0047] It should be noted that there are multiple electrodes, and the interval between the electrodes is 5 - 20 μm.

[0048] In particular, the cross-section of the gallium nitride microwire 40 is triangular; one side of the triangle is in contact with the inner side wall of the groove 101; the growth height of the gallium nitride microwire 40 is preferably 3.7 - 4.2 μm. When its growth height is between 3.7 - 4.2 μm, the gallium nitride microwire 40 will grow into a shape with a triangular cross-section. If the growth height is too small, the cross-section of the finally grown microwire is trapezoidal, with larger defects; if the height is too large, the two microwires will touch each other after growth, resulting in the top breaking and too large leakage current; when growing the gallium nitride microwire 40, the set interval between the two gallium nitride microwires 40 needs to be 50 - 200 nm, preferably 80 nm. During growth, if the two gallium nitride microwires 40 are too close, it is easy to cause overlap and fuse, so the interval between the two gallium nitride microwires 40 cannot be too small; while being too large will cause the tops of the two grown microwires not to touch each other, resulting in too large leakage current. When the interval between the two gallium nitride microwires 40 is 80 nm, the cross-section of the grown microwire is triangular, and the tops of the microwires can touch each other but do not overlap, and no fusing phenomenon will occur.

[0049] As a preferred embodiment, an aluminum nitride buffer layer 50 is provided between the inner sidewall of the groove 101 and the gallium nitride micro-wire 40, and the thickness of the aluminum nitride buffer layer 50 is 30 to 300 nm. By adding the aluminum nitride buffer layer 50, gallium nitride with better quality can be grown during the growth of gallium nitride; in addition, the aluminum nitride buffer layer 50 can also play an insulating role to prevent current from flowing out from the silicon. The thickness of the aluminum nitride buffer layer 50 is set to 30 to 300 nm. If the thickness of the aluminum nitride buffer layer 50 is less than 30, it will not play an insulating role, and if it is greater than 300, a piece of aluminum nitride will be formed in the groove, including on the insulating layer 102, so that gallium nitride may grow and extend into the insulating layer 102, resulting in an increase in dark current.

[0050] As a preferred embodiment, the groove 101 is preferably an inverted trapezoidal groove, that is, its cross-section is an inverted trapezoid. The width of the upper end of the groove 101 is 8 to 12 μm, the depth of the groove 101 is 2.5 to 4 μm, and the distance between two adjacent grooves 101 is 10 μm. The groove 101 has the function of restricting the growth area and shape of the micro-wire. The inverted trapezoidal groove enables the micro-wire to better grow into a micro-wire with a triangular cross-section, so that the tops of the two gallium nitride micro-wires grown on the inner sidewalls of the groove can be in contact with each other but not overlap, avoiding problems such as a large area of lattice mismatch and a large number of defects due to the overlap between films in a thin film structure, and improving the crystal quality.

[0051] As a preferred embodiment, the thickness of the methylammonium lead iodide layer 20 is preferably 200 to 400 nm. When the thickness of the methylammonium lead iodide layer 20 is less than 200, the light absorption efficiency is not high, resulting in a low response efficiency; while when it is higher than 400, the photo-generated carriers cannot be transported into the gallium nitride micro-wire 40, hindering the transport of carriers.

[0052] Please refer to Figures 8 to 13 , the photodetector provided by the present invention has a current (dark current) of 10 -10 A under a 5V external voltage and no light illumination, and different currents (photo-currents) are generated under illumination with different wavelengths and intensities of 325 nm, 532 nm, and 750 nm. Under illumination with 7.5 mw / cm 2 at 325 nm, the current is increased by 2240 times; under illumination with 27.4 mw / cm 2 at 532 nm, the photo-current is increased by 98 times; under illumination with 0.3 mw / cm 2 at 750 nm, the current is increased by 23 times. Under an external voltage of 5V and illumination with 7.5 mw / cm at 325 nm 2Under light irradiation, when the light source is removed, the decay time of the photocurrent is 1.51 ms; at an applied voltage of 5 V, 532 nm, 27.4 mw / cm 2 Under irradiation, when the light source is removed, the decay time of the photocurrent is 1.58 ms; at an applied voltage of 5 V, 750 nm, 0.3 mw / cm 2 Under light irradiation, when the light source is removed, the decay time of the photocurrent is 1.64 ms. When light is provided again, the rise times of the photocurrent are 6.68 ms, 1.17 ms, and 1.64 ms respectively. These data illustrate the feasibility of the photodetector of the present invention, and its detection range is relatively long. (Note: The rise time refers to the time required for the dark current to rise to 90% of the stable current when light is applied, and the decay time refers to the time required for the photocurrent to decay to 10% of the original stable value when light is removed. MW / cm 2 represents the optical power density, which indicates the intensity of light irradiation received per square centimeter. The greater the optical power density, the stronger the light irradiation.)

[0053] Due to lattice mismatch and thermal mismatch during the growth of thin film materials, a large number of defects and dislocations are generated in the epitaxial thin film, reducing the device performance; while the micron wires prepared by the present invention overcome the above problems existing in thin film materials, and a micron wire array with high crystal quality can be obtained, improving the device performance.

[0054] In addition, the present invention also provides a method for preparing a gallium nitride micron wire array photodetector, including the following steps:

[0055] Etch a plurality of equally spaced grooves on the upper surface of a silicon substrate covered with an insulating layer;

[0056] Epitaxially grow gallium nitride micron wires on the two inner sidewalls of the grooves by metal-organic chemical vapor deposition to form a micron wire array, and the extending direction of the gallium nitride micron wires is the same as the extending direction of the grooves;

[0057] After growing the gallium nitride micron wires, deposit electrodes on the upper surface of the silicon substrate;

[0058] After depositing the electrodes, coat a layer of methylammonium lead iodide on the upper surface of the silicon substrate to cover the electrodes and the gallium nitride micron wires, thereby forming a double heterojunction.

[0059] As a preferred embodiment, before growing the gallium nitride micron wires, it further includes the steps of: epitaxially growing a layer of aluminum nitride buffer layer on the inner sidewalls of the grooves by metal-organic chemical vapor deposition; and epitaxially growing the gallium nitride micron wires on the aluminum nitride buffer layer.

[0060] As a preferred embodiment, the step of etching a plurality of equally spaced grooves on the upper surface of a silicon substrate covered with an insulating layer specifically is:

[0061] An insulating material is prepared on the front surface of a clean silicon substrate to form an insulating layer. The substrate is a 2-inch intrinsic silicon wafer, and the resistivity of the silicon wafer substrate is >10 5 Ω·cm. A 300-nm-thick silicon dioxide insulating layer is formed on the surface of the silicon wafer by thermal reduction method;

[0062] Photoresist is spin-coated on the surface of the insulating layer, and periodic strip-shaped epitaxial patterns are exposed on the surface of the insulating layer through pre-baking, exposure, post-baking, and development. The thickness of the photoresist is 2 μm; the width of each stripe spacing is 10 μm;

[0063] The upper surface of the silicon substrate is selectively etched according to the strip-shaped epitaxial pattern, and then the photoresist on the silicon substrate is removed. The selective etching uses buffered etching solution (BOE) to etch the silicon dioxide insulating layer without photoresist protection, forming an alternating pattern of 10-μm silicon substrate and 10-μm silicon dioxide layer protected by photoresist. Then, acetone and isopropyl alcohol are used to remove the photoresist, and then deionized water is used for cleaning.

[0064] According to the required groove depth, after removing the photoresist, the part of the silicon substrate not covered with the insulating layer is etched wet-timed to form a plurality of equally spaced parallel grooves. The solution used is a strong base solution (a mixed solution of potassium hydroxide and isopropyl alcohol). The obtained substrate is cleaned with deionized water and the water on the surface of the substrate is blown dry using a nitrogen gas gun.

[0065] As a preferred embodiment, the deposition of the electrode on the upper surface of the silicon substrate is specifically as follows: Au metal is evaporated or sputtered on the side of the silicon substrate with gallium nitride micro-wires by thermal evaporation or ion sputtering method to form a metal electrode. Specifically, photolithography is used for photolithography of the electrode, and the spacing between the metal electrodes is 20 μm. The substrate obtained after photolithography of the electrode is thermally evaporated to evaporate Au metal; after evaporation of the epitaxial structure, the photoresist is removed and cleaning and other treatments are carried out.

[0066] As a preferred embodiment, the coating of the lead methylammonium iodide layer on the upper surface of the silicon substrate is specifically as follows: spin-coating the lead methylammonium iodide layer on the upper surface of the silicon substrate in a glove box. Specifically, transfer the gallium nitride microwire array with the metal evaporated thereon into the glove box, and spin-coat the lead methylammonium iodide solution prepared in the glove box onto the gallium nitride microwire array and the metal electrode using a spin coater. The steps of spin-coating the lead methylammonium iodide are as follows: set the rotation speed of the spin coater to 700 r / 3 s and 4000 r / 25 s; use a pipette to aspirate 60 μl of the solution onto the GaN microwire array, and add 100 μl of chlorobenzene at 18 s; set the hot stage to 45 °C and anneal for 30 min, then set it to 105 °C and anneal for 5 min. The obtained lead methylammonium iodide layer has a thickness of 200 - 400 nm.

[0067] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.

Claims

1. A gallium nitride micro-wire array photodetector, characterized in that, Comprising: A silicon substrate, a methylammonium lead iodide layer, and an electrode; a plurality of grooves arranged in parallel are formed on the upper surface of the silicon substrate; an insulating layer covers the surface of the convex portions on the upper surface of the silicon substrate; gallium nitride micro-wires are epitaxially grown on the two inner sidewalls of the grooves respectively, the extending direction of the gallium nitride micro-wires is the same as the extending direction of the grooves, and the gallium nitride micro-wires form a parallel micro-wire array; the electrode is disposed on the upper surface of the silicon substrate, and the methylammonium lead iodide layer is coated on the upper surface of the silicon substrate to cover the electrode and the gallium nitride micro-wires, thereby forming a double heterojunction.

2. The gallium nitride micro wire array photodetector according to claim 1, wherein An aluminum nitride buffer layer is provided between the gallium nitride micro-wires and the inner sidewalls of the grooves.

3. The gallium nitride microwire array photodetector according to claim 2, characterized in that, The thickness of the aluminum nitride buffer layer is 30 to 300 nm.

4. The gallium nitride micro-wire array photodetector according to claim 1, wherein, The width of the grooves is 8 to 12 μm, and the depth of the grooves is 2.5 to 4 μm.

5. The gallium nitride micro-wire array photodetector according to claim 1, characterized in that, The thickness of the methylammonium lead iodide layer is 200 to 400 nm.

6. A preparation method of a gallium nitride micro-wire array photodetector, characterized in that, Including the following steps: Etching a plurality of grooves arranged at equal intervals on the upper surface of the silicon substrate covered with an insulating layer; Epitaxially growing gallium nitride micro-wires on the two inner sidewalls of the grooves to form a micro-wire array, and the extending direction of the gallium nitride micro-wires is the same as the extending direction of the grooves; After growing the gallium nitride micro-wires, depositing an electrode on the upper surface of the silicon substrate; After depositing the electrode, coating a methylammonium lead iodide layer on the upper surface of the silicon substrate to cover the electrode and the gallium nitride micro-wires, thereby forming a double heterojunction.

7. The preparation method of the gallium nitride micro-wire array photodetector according to claim 6, wherein, Before growing the gallium nitride micro-wires, there are also steps: epitaxially growing a layer of aluminum nitride buffer layer on the inner sidewalls of the grooves by metalorganic chemical vapor deposition; epitaxially growing the gallium nitride micro-wires on the aluminum nitride buffer layer.

8. The preparation method of the gallium nitride micro-wire array photodetector according to claim 6, characterized in that, The step of etching a plurality of grooves arranged at equal intervals on the upper surface of the silicon substrate covered with an insulating layer specifically is: Preparing an insulating material on the front surface of the clean silicon substrate to form an insulating layer; Spin-coating a photoresist on the surface of the insulating layer, and making the surface of the insulating layer expose a periodically arranged strip-shaped epitaxial pattern through pre-baking, exposure, post-baking, and development; Selectively etching the upper surface of the silicon substrate according to the strip-shaped epitaxial pattern, and then performing a stripping process on the silicon substrate; According to the required groove depth, after removing the glue, performing timed wet etching on the portion of the silicon substrate not covered with the insulating layer to form a plurality of grooves arranged in parallel at equal intervals.

9. The method for preparing a gallium nitride microwire array photodetector according to claim 6, characterized in that, The step of depositing an electrode on the upper surface of the silicon substrate specifically is: evaporating or sputtering Au on the surface of the silicon substrate provided with gallium nitride micro-wires by thermal evaporation or ion sputtering to form a metal electrode.

10. The preparation method of the gallium nitride microwire array photodetector according to claim 6, wherein, The step of coating a methylammonium lead iodide layer on the upper surface of the silicon substrate specifically is: spin-coating a methylammonium lead iodide layer on the upper surface of the silicon substrate in a glove box.

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