Near-infrared response enhanced thin-layer nano array structure InGaAsP photoelectric cathode assembly and preparation method thereof

Abstract

The invention provides a thin-layer transmission type In < 0.88 > Ga < 0.12 > As < 0.26 > P < 0.74 > photoelectric cathode assembly with enhanced near-infrared response. The photoelectric cathode assembly structurally comprises an In < 0.88 > Ga < 0.12 > As < 0.26 > P < 0.74 > emission layer, an In < 0.52 > Al < 0.48 > As window layer, a Si3N4 anti-reflection layer and glass from bottom to top. The In0. 52Al0. 48As window layer comprises a plane layer and a nano-structure array, gaps between nano structures are filled with Si3N4 media, the nano-structure array part adopts a plurality of cylinder or square column structures which are periodically distributed, and by adjusting the period, the shape, the size and the arrangement mode of the nano-structure array structure, the nano-structure array structure can be obtained. The absorption rate of the whole photoelectric cathode assembly at the near-infrared specific wavelength can be improved, so that the quantum efficiency of the transmission-type In < 0.88 > Ga < 0.12 > As < 0.26 > P < 0.74 > photoelectric cathode at the near-infrared specific wavelength is improved. The invention also provides a preparation process flow of the In < 0.88 > Ga < 0.12 > As < 0.26 > P < 0.74 > photoelectric cathode assembly, which is compatible with an emerging micro-nano machining process and a traditional inversion process.

Description

Technical Field

[0001] The invention belongs to the technical field of near-infrared photoelectric detection, and specifically relates to a thin-layer nano-array structure InGaAsP photocathode component with enhanced near-infrared response and a preparation method thereof. Background Art

[0002] Near-infrared photocathode devices are widely used in civil and military fields, such as satellite remote sensing, astronomical detection, weapon precision guidance, surveillance and reconnaissance, etc. Among them, infrared night vision devices are irreplaceable in military night detection. When there is no moonlight at night, the main object of night detection is night sky light, and the energy of the visible light range in the night sky light spectrum is 1 to 2 orders of magnitude lower than that in the near-infrared band. This places high demands on the near-infrared band response capability and long-wave threshold of night vision devices. Early near-infrared photodetectors usually used Ag-O-Cs photocathodes with poor emission performance and short long-wave thresholds. Later, the emergence of GaAs photocathodes made domestic and foreign scholars pay attention to the great potential of the adjustable band gap characteristics of III-V semiconductor materials in near-infrared photocathodes research. With the maturity of NEA GaAs photocathodes and people's in-depth research on III-V semiconductor materials, near-infrared responsive photocathodes such as InGaAsP and InGaAs were invented. These near-infrared photocathodes extended the long-wave threshold outward and improved the response capability. Compared with the low-light image intensifier made of traditional NEAGaAs photocathode, the peak response is mainly between 600nm and 750nm, and the threshold wavelength does not exceed 930nm, which has low efficiency in night sky light detection. The long-wave limit of the near-infrared photocathode made of InGaAsP, InGaAs and other materials has been increased to more than 1100nm, which greatly improves the long-wave limit and can well cover the full band of night sky light and enhance night vision effects.

[0003] As a multi-element material, InGaAsP can control the band gap size by adjusting the element composition, thereby extending the long-wave threshold of the near-infrared photocathode. It is an important near-infrared photocathode material. Considering that the lattice matching of the material will affect the quality of the epitaxial growth of the photocathode material, which has an important influence on its photoelectric emission performance, the preparation and selection of the transmission InGaAsP photocathode component are similar to InGaAsP. 0.88 Ga 0.12 As 0.26 P 0.74 Lattice-matched InP is used as the substrate for epitaxial growth of materials. 0.52 Al 0.48As acts as a corrosion barrier and window layer. In addition, the photoelectric performance of the transmissive InGaAsP photocathode is also restricted by the contradictory effect of the emission layer thickness on the absorptivity and photoelectric emission performance: if the emission layer is thick, the photocathode can absorb light more fully, but the response speed becomes slower, the electron transport loss is more, and the lateral diffusion becomes stronger; if the emission layer is thin, the photocathode has a faster response speed, less transport loss and weaker lateral diffusion, but sacrifices the light absorption rate. Summary of the invention

[0004] The purpose of the present invention is to provide a thin-layer nano-array structure InGaAsP photocathode component with enhanced near-infrared response.

[0005] The technical solution to achieve the purpose of the present invention is: a thin-layer nano-array structure InGaAsP photocathode component with enhanced near-infrared response, comprising InGaAsP arranged from bottom to top 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer, In 0.52 Al 0.48 As window layer, Si3N4 anti-reflection layer and glass, wherein the In 0.52 Al 0.48 As window layer includes In 0.52 Al 0.48 As plane layer and set in In 0.52 Al 0.48 In As plane layer 0.52 Al 0.48 As nanostructure arrays.

[0006] Preferably, the In 0.88 Ga 0.12 As 0.26 P 0.74 The emission layer material is p-type doped material with a doping concentration of 1×10 18 ~1×10 19 cm -3 , thickness is 500~3000nm.

[0007] Preferably, the In 0.52 Al 0.48 The As window layer is a p-type doped material with a doping concentration of 1×10 18 ~1×10 19 cm -3 , thickness is 100~600nm.

[0008] Preferably, Si3N4 dielectric is used to fill In 0.52 Al 0.48The gaps in the As nanostructure array are filled, and a 100-400 nm thick Si3N4 anti-reflection layer is formed on the nanoarray structure.

[0009] Preferably, the In 0.52 Al 0.48 The thickness of the As planar layer is 50 to 400 nm.

[0010] Preferably, the In 0.52 Al 0.48 As nanostructure arrays are periodically arranged on In 0.52 Al 0.48 The cylindrical or square column structure on the As plane layer has a cylindrical structure with a period of 200 to 800 nm, a cylindrical height of 50 to 500 nm, and a diameter of 100 to 600 nm; the square column structure has a period of 200 to 800 nm, a square column height of 50 to 500 nm, and a width of 100 to 600 nm.

[0011] The present invention proposes a nano-array structure transmission In 0.88 Ga 0.12 As 0.26 P 0.74 The preparation method of the photocathode assembly comprises the following specific steps:

[0012] Step 1: epitaxially grow In on an InP substrate 0.52 Al 0.48 As corrosion barrier layer, In 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer and In 0.52 Al 0.48 As window layer, then PECVD deposition of Si3N4 dielectric;

[0013] Step 2, using a spin coating method to evenly cover the Si3N4 medium with the photoresist;

[0014] Step 3: Make the Si3N4 dielectric layer have the same properties as In by electron beam exposure or nanosphere self-assembly process. 0.52 Al 0.48 A mask with a consistent nanoarray structure pattern in the As window layer;

[0015] Step 4: Using the Si3N4 dielectric layer as a mask, etch the In 0.52 Al 0.48 As window layer, forming a periodically distributed nano-array structure, and removing the Si3N4 dielectric layer through selective etching by specific chemical reagents;

[0016] Step 5. Once again in In 0.52Al 0.48 A Si3N4 medium is deposited on the As window layer to completely fill the gaps in the nanoarray structure and to form a Si3N4 anti-reflection layer above the structure;

[0017] Step 6, thermally bonding the glass to the Si3N4 anti-reflection layer;

[0018] Step 7: Immerse the sample in a mixed solution of HCl:H3PO4:CH3COOH to selectively etch and remove the InP substrate layer, and immerse the sample in a mixed solution of HCl:H2O to remove the In 0.52 Al 0.48 As corrosion barrier;

[0019] Step 8: Through ultra-high vacuum activation process, 0.88 Ga 0.12 As 0.26 P 0.74 A Cs / O or Cs / NF3 activation layer is formed on the surface of the emission layer, and finally the In 0.88 Ga 0.12 As 0.26 P 0.74 Cathode assembly.

[0020] Compared with the prior art, the present invention has the following significant advantages: 1) the lattice matching of each layer of the material adopted in the present invention and the good quality of epitaxial growth ensure the photoelectric emission performance of the photocathode assembly; 2) the present invention adopts a nano-array structure to improve the absorption rate of the photocathode assembly to light of a specific near-infrared wavelength, thereby improving the quantum efficiency of the photocathode at the specific near-infrared wavelength; 3) the present invention can enhance the quantum efficiency of the photocathode at the target wavelength by changing the appearance properties of the nano-array structure, including the shape, arrangement period, line width, height and arrangement mode of the nano-structure; 4) the cut-off wavelength of the present invention is in the near-infrared band, and the quantum efficiency for incident light with a wavelength near the specific near-infrared band is high, and it is not easily disturbed by incident light of irrelevant bands.

[0021] The present invention is described in further detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the photocathode assembly.

[0023] Figure 2 This is a top view of a square arrangement of cylindrical nanostructure arrays.

[0024] Figure 3 This is a top view of the staggered arrangement of 1 / 2 cylindrical nanostructure arrays.

[0025] Figure 4 This is a top view of a square-arranged array of square-pillar nanostructures.

[0026] Figure 5 This is a top view of the staggered arrangement of 1 / 2 cylindrical nanostructure arrays.

[0027] Figure 6 It is a comparison chart of the relationship between the photocathode light absorption rate and the wavelength of the incident light (line width 440nm).

[0028] Figure 7 It is a comparison chart of the relationship between the photocathode light absorption rate and the wavelength of the incident light (line width 360nm).

[0029] Figure 8 It is a comparison chart of the relationship between the photocathode light absorption rate and the wavelength of the incident light (line width 240nm). DETAILED DESCRIPTION

[0030] like Figure 1 As shown, a thin-layer nano-array structure InGaAsP photocathode component with enhanced near-infrared response includes In 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer, In 0.52 Al 0.48 As window layer, Si3N4 anti-reflection layer and glass, wherein the In 0.52 Al 0.48 As window layer includes In 0.52 Al 0.48 As plane layer and set in In 0.52 Al 0.48 In As plane layer 0.52 Al 0.48 As nanostructure arrays.

[0031] In a further embodiment, the In 0.88 Ga 0.12 As 0.26 P 0.74 The emission layer material is p-type doped material with a doping concentration of 1×10 18 ~1×10 19 cm -3 , thickness is 500~3000nm.

[0032] In a further embodiment, the In 0.52 Al 0.48 The As window layer is a p-type doped material with a doping concentration of 1×10 18 ~1×10 19 cm -3 , thickness is 100~600nm.

[0033] In a further embodiment, Si3N4 dielectric is used to fill In 0.52 Al 0.48 The gaps in the As nanostructure array are filled, and a 100-400 nm thick Si3N4 anti-reflection layer is formed on the nanoarray structure.

[0034] In a further embodiment, the thickness of the Si3N4 anti-reflection layer is (2k+1)λ / 4n, wherein n is the refractive index, k is a non-negative integer, and λ is the target wavelength.

[0035] In a further embodiment, the In 0.52 Al 0.48 The thickness of the As planar layer is 50 to 400 nm.

[0036] In a further embodiment, the In 0.52 Al 0.48 As nanostructure arrays are periodically arranged on In 0.52 Al 0.48 The cylindrical or square column structure on the As plane layer has a cylindrical structure with a period of 200 to 800 nm, a cylindrical height of 50 to 500 nm, and a diameter of 100 to 600 nm; the square column structure has a period of 200 to 800 nm, a square column height of 50 to 500 nm, and a width of 100 to 600 nm.

[0037] In a further embodiment, the material of the Si3N4 anti-reflection layer is Si3N4 material with a refractive index of 2.01 and a thickness of 130 nm.

[0038] The present invention also provides a nano-array structure In 0.88 Ga 0.12 As 0.26 P 0.74 The preparation method of the photocathode assembly comprises the following specific steps:

[0039] Step 1: epitaxially grow In on an InP substrate 0.52 Al 0.48 As corrosion barrier layer, In 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer and In 0.52 Al 0.48 As window layer, then PECVD deposition of Si3N4 dielectric;

[0040] Step 2, using a spin coating method to evenly cover the Si3N4 medium with the photoresist;

[0041] Step 3: Make the Si3N4 dielectric layer have the same properties as In by electron beam exposure or nanosphere self-assembly process. 0.52 Al0.48 A mask with a consistent nanoarray structure pattern in the As window layer;

[0042] Step 4: Using the Si3N4 dielectric layer as a mask, etch the In 0.52 Al 0.48 As window layer, forming a periodically distributed nano-array structure, and removing the Si3N4 dielectric layer through selective etching by specific chemical reagents;

[0043] Step 5. Once again in In 0.52 Al 0.48 A Si3N4 medium is epitaxially grown on the As window layer to completely fill the gaps in the nanoarray structure, and a Si3N4 anti-reflection layer is grown;

[0044] Step 6, thermally bonding the glass to the Si3N4 anti-reflection layer;

[0045] Step 7: Immerse the sample in a mixed solution of HCl:H3PO4:CH3COOH to selectively etch and remove the InP substrate layer, and immerse the sample in a mixed solution of HCl:H2O to remove the In 0.52 Al 0.48 As corrosion barrier;

[0046] Step 8: Through ultra-high vacuum activation process, 0.88 Ga 0.12 As 0.26 P 0.74 A Cs / O or Cs / NF3 activation layer is formed on the surface of the emission layer, and finally the In 0.88 Ga 0.12 As 0.26 P 0.74 Cathode assembly.

[0047] like Figure 6 , 7 , as shown in 8, In 0.52 Al 0.48 A nanoarray structure is constructed on the As window layer, which improves the absorptivity of the photocathode component at wavelengths of 1075nm, 1064nm and 1050nm, thereby helping to improve the quantum efficiency of the photocathode component at specific near-infrared wavelengths.

[0048] As an embodiment, the thickness of the Si3N4 anti-reflection layer is 130nm; the Si3N4 filling medium is used to fill the gaps between the micro-nano structure arrays; the In having a micro-nano structure array 0.52 Al 0.48 The As window layer material is p-type doped with a doping concentration of 1×10 19 cm -3, with a thickness of 200nm, of which the nanoarray structure height is 150nm and the planar layer height is 50nm.

[0049] As an embodiment, the application of the transmissive In 0.88 Ga 0.12 As 0.26 P 0.74 The nanometer array structure obtained by the preparation method of the photocathode component is a cylindrical or square column nanometer array structure arranged in a square period, such as Figure 2 , Figure 4 As shown, the nanoarray structure period P is 585nm, the structure height is 150nm, the plane layer height is 50nm, and the structure line width is: the cylindrical line width a is 440nm; the square column line width a is 400nm.

[0050] As an embodiment, the nanoarray structure is a 1 / 2 staggered cylindrical or square column nanoarray structure, such as Figure 3 , Figure 5 As shown. The arrangement period P of the nanoarray structure is 585nm, and the row offset distance of the staggered periodic arrangement is equal to 1 / 2 of the arrangement period, that is, P / 2 is 292.5nm. The height of the nanoarray structure is 150nm, the plane layer height is 50nm, and the structure line width is: the cylindrical line width a is 440nm; the square column line width a is 400nm.

[0051] The present invention is based on the theory of micro-nano optics. Micro-nano structures have the potential to improve the light absorption of photocathode. Therefore, introducing a micro-nano array structure into the window layer of the transmissive InGaAsP photocathode can effectively improve the light absorption rate without increasing the thickness of the emission layer, thereby improving the photoelectric emission performance of the thin-layer transmissive InGaAsP photocathode.

[0052] The thin-layer nano-array structure InGaAsP photocathode component with enhanced near-infrared response of the present invention improves the absorption rate at a specific near-infrared wavelength, is not easily disturbed by incident light of irrelevant wavelength bands, and can be applied to various photoelectric devices such as pulse laser seed sources; and the present invention provides a complete photocathode component preparation process flow that is compatible with micro-nano processing technology and traditional inversion technology, and obtains a transmissive InGaAsP nano-array structure with good periodicity and complete morphology. 0.88 Ga 0.12 As 0.26 P 0.74 Photocathode assembly.

[0053] Example 1

[0054] Nano-array structure In prepared by electron beam lithography 0.88 Ga 0.12 As 0.26 P 0.74Photocathode:

[0055] First, InP was grown on an intrinsic InP substrate by molecular beam epitaxy. 0.52 Al 0.48 As corrosion barrier layer, In 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer and In 0.52 Al 0.48 As window layer, and then PECVD deposited Si3N4 dielectric.

[0056] The Si3N4 medium is evenly covered with photoresist by spin coating, and electron beam exposure is performed first, and then developed with a developer, and the developer is removed to obtain a photoresist layer with a circular array pattern with a period of 585nm and a line width of 440nm.

[0057] The pattern of the photoresist layer is etched to the Si3N4 dielectric layer by reactive ion etching technology; the In2O3 dielectric layer is etched by inductively coupled plasma etching technology using the Si3N4 dielectric layer as a mask. 0.52 Al 0.48 As window layer, a nano-array structure with a periodic distribution of 150nm in height and a planar layer with a height of 50nm are formed.

[0058] Si3N4 and photoresist are still retained on the nano-array structure. The residual photoresist is washed away with butanone, and the Si3N4 dielectric layer is selectively etched away by a specific chemical reagent. The Si3N4 material is deposited to 130nm above the structure by plasma enhanced chemical vapor deposition to obtain a Si3N4 anti-reflection layer and an In nano-array structure with a cylindrical or square columnar array structure having a structure gap filled with Si3N4 dielectric. 0.52 Al 0.48 As window layer.

[0059] The glass is thermally bonded to the Si3N4 anti-reflection layer.

[0060] The sample was immersed in a mixed solution of HCl:H3PO4:CH3COOH to selectively etch and remove the InP substrate layer, and the sample was immersed in a mixed solution of HCl:H2O to remove the In 0.52 Al 0.48 As corrosion barrier layer.

[0061] The components are placed in an ultra-high vacuum system for high-temperature purification. After cooling, a Cs / O or Cs / NF3 activation layer is attached to the clean emission layer surface to finally prepare a nano-array structure In 0.88 Ga 0.12 As 0.26 P 0.74 Photocathode assembly.

[0062] like Figure 6 As shown, when the cylindrical line width is 440nm, the light absorption of the cathode of the present invention at 1075nm is significantly enhanced compared with the traditional cathode, thereby helping to improve the quantum efficiency of the photocathode assembly at a specific wavelength in the near-infrared.

[0063] Example 2

[0064] Different from Example 1, the nanoarray structure In 0.88 Ga 0.12 As 0.26 P 0.74 Nanostructured arrays of photocathode components In 0.52 Al 0.48 The nano-array structure of the As window layer is a cylindrical or square column. The nano-array structure adopts a square or 1 / 2 staggered periodic arrangement with a period P of 500nm and a structure height of 150nm. 0.52 Al 0.48 The As plane layer is 50nm; the structure line width is: the cylindrical line width a is 440nm; the square column line width a is 400nm.

[0065] Example 3

[0066] Different from Example 1, a photoresist having a circular array pattern with a period of 585 nm and line widths of 360 nm and 240 nm is obtained by electron beam exposure or nanoimprinting; the photoresist having the pattern is used as a mask, and the pattern is etched onto the Si3N4 dielectric layer by reactive ion etching technology; the Si3N4 dielectric layer is used as a mask, and the pattern is etched onto the In2O3 dielectric layer by inductively coupled plasma etching technology. 0.52 Al 0.48 On the As window layer, an In nanostructured cylindrical array is obtained. 0.52 Al 0.48 As window layer. 0.52 Al 0.48 The cylindrical array period of the As window layer is 585nm, the cylinder height is 150nm, and the In window layer 0.52 Al 0.48 When the As plane layer is 50nm, and the cylindrical line width is 360nm, Figure 7 As shown in FIG. 1 , the light absorption of the cathode of the present invention at 1064 nm is significantly enhanced compared with the traditional cathode; when the cylindrical line width is 240 nm, as shown in FIG. Figure 8 As shown, the light absorption of the cathode of the present invention at 1050 nm is significantly enhanced, which is helpful to improve the quantum efficiency of the cathode.

[0067] Example 4

[0068] Preparation of nanoarray structure In by self-assembled nanosphere method 0.88 Ga 0.12 As 0.26 P 0.74 Photocathode:

[0069] First, InP was grown on an intrinsic InP substrate by molecular beam epitaxy. 0.52 Al 0.48 As corrosion barrier layer, In 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer and In 0.52 Al 0.48 As window layer.

[0070] Different from Example 1, the In nanoarray structure is prepared by self-assembled nanosphere method. 0.52 Al 0.48 As window layer. A single layer of SiO2 nanospheres is evenly attached to the In 0.52 Al 0.48 As window layer surface, and SiO2 nanospheres were etched by reactive ion etching technology to reduce the line width of the nanospheres to 240nm, which is consistent with the target cylinder line width.

[0071] In 0.52 Al 0.48 The SiO2 nanosphere array on the surface of the As window layer is used as a mask layer to etch the In 0.52 Al 0.48 As window layer, in In 0.52 Al 0.48 A nano-array structure with a SiO2 nano-ball mask layer on top, a height of 150 nm, and a planar layer with a height of 50 nm are formed on the As window layer.

[0072] The SiO2 nanosphere mask was removed by etching with a solution of 10% HF:40% NH4F solution diluted with 10 times the volume of deionized water in a volume ratio of 1:6, and then washed with deionized water. 0.52 Al 0.48 As nanostructure array, thus completing In 0.52 Al 0.48 As window layer construction.

[0073] The Si3N4 material is deposited to 130 nm above the structure by plasma enhanced chemical vapor deposition to obtain a Si3N4 anti-reflection layer and an In2O3 array structure with a cylindrical or square columnar structure having a structure gap filled with Si3N4 medium. 0.52 Al0.48 As window layer.

[0074] The glass is thermally bonded to the Si3N4 anti-reflection layer.

[0075] The sample was immersed in a mixed solution of HCl:H3PO4:CH3COOH to selectively etch and remove the InP substrate layer, and the sample was immersed in a mixed solution of HCl:H2O to remove the In 0.52 Al 0.48 As corrosion barrier layer.

[0076] The components are placed in an ultra-high vacuum system for high-temperature purification. After cooling, a Cs / O or Cs / NF3 activation layer is attached to the clean emission layer surface to finally prepare a nano-array structure In 0.88 Ga 0.12 As 0.26 P 0.74 Photocathode assembly.

[0077] The present invention constructs a nanostructure array on the window layer of the photocathode assembly by using a preparation process flow that is compatible with the emerging micro-nano processing technology and the traditional inversion process. By adjusting the morphology of the nanoarray structure, the absorption rate of the photocathode assembly at a specific wavelength can be improved, thereby ultimately improving the quantum efficiency of the photocathode assembly at a specific wavelength.

Claims

1. A thin-layer nano-array structure InGaAsP photocathode component with enhanced near-infrared response, characterized in that: Including bottom-up settings 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer (1), In 0.52 Al 0.48 As window layer (2), Si3N4 anti-reflection layer (3) and glass (4), wherein the In 0.52 Al 0.48 As window layer (2) includes In 0.52 Al 0.48 As plane layer and set in In 0.52 Al 0.48 In As plane layer 0.52 Al 0.48 As nanostructure arrays.

2. The thin-layer nano-array structure InGaAsP photocathode assembly with enhanced near-infrared response according to claim 1, characterized in that: In 0.88 Ga 0.12 As 0.26 P 0.74 The material of the emission layer (1) is a p-type doped material with a doping concentration of 1×10 18 ~1×10 19 cm -3 , thickness is 500~3000nm.

3. The thin-layer nano-array structure InGaAsP photocathode assembly with enhanced near-infrared response according to claim 1, characterized in that: In 0.52 Al 0.48 The As window layer (2) is a p-type doping material with a doping concentration of 1×10 18 ~1×10 19 cm -3 , thickness is 100~600nm.

4. The InGaAsP photocathode assembly with a thin layer nano-array structure having enhanced near infrared response according to claim 3 0.52 Al 0.48 As window layer, characterized in that Use Si3N4 dielectric to fill In 0.52 Al 0.48 The gaps in the As nanostructure array are higher than the set height of the nanoarray structure, serving as a Si3N4 anti-reflection layer (3).

5. The Si3N4 anti-reflection layer of the thin-layer nano-array structure InGaAsP photocathode assembly with enhanced near-infrared response according to claim 4, characterized in that: The thickness of the Si3N4 anti-reflection layer is (2k+1)λ / 4n, where n is the refractive index, k is a non-negative integer, and λ is the target wavelength.

6. The thin-layer nano-array structure InGaAsP photocathode assembly with enhanced near-infrared response according to claim 1, characterized in that: In 0.52 Al 0.48 The thickness of the As planar layer is 50 to 400 nm.

7. The thin-layer nano-array structure InGaAsP photocathode assembly with enhanced near-infrared response according to claim 1, characterized in that: In 0.52 Al 0.48 As nanostructure arrays are periodically arranged on In 0.52 Al 0.48 The cylindrical or square column structure on the As plane layer has a cylindrical structure with a period of 200 to 800 nm, a cylindrical height of 50 to 500 nm, and a diameter of 100 to 600 nm; the square column structure has a period of 200 to 800 nm, a square column height of 50 to 500 nm, and a width of 100 to 600 nm.

8. A method for preparing a thin-layer nano-array structure InGaAsP photocathode assembly with enhanced near-infrared response as claimed in any one of claims 1 to 7, characterized in that: The specific steps are: Step 1: epitaxially grow In on an InP substrate 0.52 Al 0.48 As corrosion barrier layer, In 0.88 Ga 0.12 As 0.26 P 0.74 Emission layer and In 0.52 Al 0.48 As window layer, then PECVD deposition of Si3N4 dielectric; Step 2, using a spin coating method to evenly cover the Si3N4 medium with the photoresist; Step 3: Make the Si3N4 dielectric layer have the same properties as In by electron beam exposure or nanosphere self-assembly process. 0.52 Al 0.48 A mask with a consistent nanoarray structure pattern in the As window layer; Step 4: Using the Si3N4 dielectric layer as a mask, etch the In 0.52 Al 0.48 As window layer, forming a periodically distributed nano-array structure, and removing the Si3N4 dielectric layer through selective etching by specific chemical reagents; Step 5. Once again in In 0.52 Al 0.48 A Si3N4 medium is deposited on the As window layer to completely fill the gaps in the nanoarray structure and to form a Si3N4 anti-reflection layer above the structure; Step 6, thermally bonding the glass to the Si3N4 anti-reflection layer; Step 7: Immerse the sample in a mixed solution of HCl:H3PO4:CH3COOH to selectively etch and remove the InP substrate layer, and immerse the sample in a mixed solution of HCl:H2O to remove the In 0.52 Al 0.48 As corrosion barrier; Step 8: Through ultra-high vacuum activation process, 0.88 Ga 0.12 As 0.26 P 0.74 A Cs / O or Cs / NF3 activation layer is formed on the surface of the emission layer, and finally the In 0.88 Ga 0.12 As 0.26 P 0.74 Cathode assembly.

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