Preparation method of high-reflectivity AlGaN-based distributed Bragg reflector

Abstract

The embodiment of the invention provides a preparation method of a high-reflectivity AlGaN-based distributed Bragg reflector. The preparation method comprises the steps that an AlN layer and an n-Al < x > Ga < 1-x > N current expansion layer which are stacked are sequentially deposited on a substrate; a plurality of n-Al < y > Ga < 1-y > N layers and a plurality of n +-Al < z > Ga < 1-z > N layers which are stacked alternately grow on the n-Al < x > Ga < 1-x > N current expansion layer to obtain an epitaxial wafer, and the n +-Al < z > Ga < 1-z > N layers are located among the n-Al < y > Ga < 1-y > N layers; depositing a protective layer on the epitaxial wafer, and removing the protective layer and the stacked AlGaN structure in a preset region on the n-Al < x > Ga < 1-x > N current expansion layer; placing the epitaxial wafer on which the protection layer is formed in an electrolyte, connecting the n-Al < x > Ga < 1-x > N current expansion layer with a power supply anode, and connecting the electrolyte with a power supply cathode; the epitaxial wafer is controlled to be subjected to electrochemical corrosion or photoelectrochemical corrosion in the electrolyte, so that a nano-porous structure is formed in the n < + >-Al < z > Ga < 1-z > N layer; and removing the residual protection layer to obtain the high-reflectivity AlGaN-based distributed Bragg reflector.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor optoelectronic device manufacturing, and particularly relates to a preparation method of a high-reflectivity AlGaN-based distributed Bragg reflector. BACKGROUND

[0002] As a key optical element, the high-reflectivity distributed Bragg reflector (DBR) has a huge application prospect and market demand in high-brightness light emitting diodes (LEDs), resonant cavity light emitting diodes (RC-LEDs), vertical-cavity surface-emitting lasers (VCSELs) and photodetectors. The GaN-based nanoporous structure DBR prepared by electrochemical etching or photoelectrochemical etching can fundamentally break through the technical barriers of the resonant cavity bottom high-reflectivity reflector due to its large refractive index difference, low loss and simple process, and has attracted widespread attention. The GaN-based nanoporous DBR used by the Han Jung team of Yale University has successfully realized the low-threshold lasing of the VCSEL in the 434 nm waveband.

[0003] With the development of nitride optoelectronic devices to the ultraviolet waveband, the preparation of high-performance DBRs still faces great challenges, and the reflectivity of the AlGaN-based nanoporous DBR is far inferior to that of the GaN-based nanoporous DBR. The main reasons include that the n-type resistivity of the AlGaN material increases with the increase of the Al component, and a part of the voltage drop is lost in the AlGaN semiconductor layer during the electrochemical etching or photoelectrochemical etching process; the current is difficult to uniformly spread from bottom to top to the entire DBR stack structure, resulting in uneven distribution of the pore size and porosity of the nanoporous structure layer, especially the low porosity near the top, which reduces the peak reflectivity of the AlGaN-based nanoporous DBR, and restricts the development of high-performance RC-LEDs and VCSELs in the ultraviolet waveband. SUMMARY

[0004] In view of the above problems, the present disclosure provides a preparation method of a high-reflectivity AlGaN-based distributed Bragg reflector, which is used to at least partially solve the above technical problems.

[0005] The present disclosure provides a preparation method of a high-reflectivity AlGaN-based distributed Bragg reflector, which comprises: sequentially depositing a stack of an AlN layer, an n-Al x Ga 1-x N current spreading layer on a substrate; etching the n-Alx Ga 1-x N current spreading layer alternately grown stack of multilayer n-Al y Ga 1-y N layer and multilayer n + -Al z Ga 1-z N layer, forming a stack AlGaN structure, to get an epitaxial wafer, wherein the multilayer n + -Al z Ga 1-z N layer is located between the multilayer n-Al y Ga 1-y N layer; deposit a protective layer on the epitaxial wafer, and remove the n-Al x Ga 1-x N current spreading layer and the stack AlGaN structure in the preset area; the epitaxial wafer formed with the protective layer is placed in an electrolyte, and the n-Al x Ga 1-x N current spreading layer is connected with the anode of a power supply, and the electrolyte is connected with the cathode of the power supply; the epitaxial wafer is controlled to perform electrochemical corrosion or photoelectrochemical corrosion in the electrolyte, so that the n + -Al z Ga 1-z N layer forms a nanoporous structure; the remaining protective layer is removed, and a high-reflectivity AlGaN-based distributed Bragg reflector is obtained.

[0006] The preparation method of the high-reflectivity AlGaN-based distributed Bragg reflector provided by the present disclosure has at least the following technical effects:

[0007] By finely modulating the doping concentration and Al component of the nanoporous layer, the voltage drop is more uniformly applied to the functional layer, the pore size and porosity of the nanoporous structure layer can be more accurately controlled, the geometric pore size and porosity of the nanoporous structure layer are uniform and consistent, and the peak reflectivity of the DBR is improved.

[0008] By accurately controlling the epitaxial doping concentration distribution and electrochemical corrosion parameters, the nanopore structure can be accurately controlled, and a customizable reflectivity (up to 99% or more) can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0009] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure, taken in conjunction with the accompanying drawings, in which:

[0010] Figure 1 A flowchart of a preparation method of a high-reflectivity AlGaN-based distributed Bragg reflector according to an embodiment of the present disclosure is schematically shown.

[0011] Figure 2A structural schematic diagram of an epitaxial wafer according to an embodiment of the present disclosure is shown schematically.

[0012] Figure 3 A structural schematic diagram of an epitaxial wafer formed with a protective layer according to an embodiment of the present disclosure is shown schematically.

[0013] Figure 4 A structural schematic diagram of an epitaxial wafer after removing n-Al x Ga 1-x A schematic diagram of a protective layer and a stacked AlGaN structure on a preset region of an n-Al

[0014] Figure 5 A structural schematic diagram of an epitaxial wafer after electrochemical or photoelectrochemical etching according to an embodiment of the present disclosure is shown schematically.

[0015] Figure 6 A schematic diagram of an apparatus for electrochemical etching according to an embodiment of the present disclosure is shown schematically.

[0016] Figure 7 An example of a reflectance spectrum of an AlGaN-based DBR prepared by a preparation method according to an embodiment of the present disclosure is shown schematically. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood, however, that the description which follows is merely exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description of the embodiments, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it would be apparent to one skilled in the art that the embodiments can be practiced without these specific details. In other instances, well-known structures and functions have not been described in detail in order to avoid obscuring the concepts of the present disclosure.

[0018] The terms used herein are merely used to describe specific embodiments and are not intended to limit the present disclosure. The terms "include", "comprise", and the like used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0019] All terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of the present specification, and should not be interpreted in an idealized or overly formal manner.

[0020] Figure 1 A flowchart of a preparation method of a high-refractive AlGaN-based distributed Bragg reflector according to an embodiment of the present disclosure is shown schematically.

[0021] As Figure 1 shown, the method for manufacturing the high-reflection AlGaN-based distributed Bragg reflector of the embodiment can include operations S110-S160.

[0022] At operation S110, a stacked AlN layer, an n-Al x Ga 1-x N current spreading layer, and an n-Ga

[0023] At operation S120, a stacked plurality of n-Al x Ga 1-x N layers and a plurality of n y Ga 1-y N layers are alternately grown on the n-Al + -Al z Ga 1-z N current spreading layer, forming a stacked AlGaN structure, to obtain an epitaxial wafer, wherein the plurality of n-Al + -Al z Ga 1-z N layers are located between the plurality of n-Al y Ga 1-y N layers.

[0024] At operation S130, a protective layer is deposited on the epitaxial wafer, and the protective layer and the stacked AlGaN structure in a preset region on the n-Al x Ga 1-x N current spreading layer are removed.

[0025] At operation S140, the epitaxial wafer with the protective layer formed thereon is placed in an electrolyte, and the n-Al x Ga 1-x N current spreading layer is connected to an anode of a power supply, and the electrolyte is connected to a cathode of the power supply.

[0026] At operation S140, electrochemical corrosion or photoelectrochemical corrosion of the epitaxial wafer in the electrolyte is controlled, so that a nanoporous structure is formed inside the n-Al + -Al z Ga 1-z N layer.

[0027] At operation S160, the remaining protective layer is removed, to obtain the high-reflection AlGaN-based distributed Bragg reflector.

[0028] According to the embodiment of the present disclosure, in the process of alternately growing the stacked plurality of n-Al y Ga 1-y N layers and the plurality of n + -Al z Ga 1-z N layers, the plurality of n-Al xGa 1-x An n-Al layer is grown on the N current spreading layer. y Ga 1-y N layers, then n-Al y Ga 1-y A layer n grows on layer N. + -Al z Ga 1-z N layers, then n + -Al z Ga 1-z An n-Al layer is grown on the N layer. y Ga 1-y N layers are grown alternately to obtain a stacked AlGaN structure, with the top layer of the stacked AlGaN structure being n-Al. y Ga 1-y N layers, that is, each adjacent n-Al y Ga 1-y A layer n is sandwiched between layers N. + -Al z Ga 1-z N layers.

[0029] According to embodiments of this disclosure, x, y, and z represent component contents, and x, y, and z satisfy 1 ≥ x > y ≥ z ≥ 0.

[0030] In some embodiments, multilayer n-Al y Ga 1-y The N-layer is lightly Si-doped n-Al. y Ga 1-y N; multi-layer n + -Al z Ga 1-z The N-layer is heavily Si-doped n + -Al z Ga 1-z N layers.

[0031] In some embodiments, along n-Al y Ga 1-y N layers point to n + -Al z Ga 1-z The direction of the N-layer, multilayer heavy Si doping n + -Al z Ga 1-z The Si doping concentration in the N-layer exhibits a step-like increase, a gradual increase layer by layer, or a periodic combination of increases; or, multiple n-layer layers... + -Al z Ga 1- z The portion n near the protective layer in layer N + -Al z Ga1-z The Si doping concentration in the N-layer increases stepwise, gradually increases layer by layer, or increases periodically in combination, with the remaining n layers showing a higher concentration. + -Al z Ga 1-z The Si doping concentration is the same in the N-layer; the heavily Si-doped n-layer... + -Al z Ga 1-z The Si doping concentration of the N layer is the same as that of lightly Si-doped n-Al. y Ga 1-y The Si doping concentration of N is more than 1.5 times that of Si.

[0032] In some embodiments, n-Al x Ga 1-x The Al content in the N-current spread layer is greater than that in the lightly Si-doped n-Al. y Ga 1-y The content of the N-layer Al component, lightly Si-doped n-Al y Ga 1-y The content of the N-layer Al component is greater than or equal to the content of the heavily Si-doped n-layer. + -Al z Ga 1-z The content of the A1 component in the N layer.

[0033] In some embodiments, along n-Al y Ga 1-y N layers point to n + -Al z Ga 1-z The direction of the N-layer, multilayer heavy Si doping n + -Al z Ga 1-z The content of Al components in the N layer gradually decreases.

[0034] In some embodiments, multilayer n-Al y Ga 1-y N-layer and multi-layer n + -Al z Ga 1-z The thickness of each layer in layer N satisfies n i ×d i =λ0 / 4, where λ0 is the center wavelength, and n i For n-Al y Ga 1-y N-layer and nanoporous morphology + -Al z Ga 1-z The refractive index of the N layer at wavelength λ0.

[0035] In some embodiments, by adjusting the corrosion conditions of electrochemical corrosion or photoelectrochemical corrosion, in n+ -Al z Ga 1- z The N layer is internally formed with a nanoporous structure with a pore size of 1 nm to 60 nm and a porosity of 1% to 80%.

[0036] In some embodiments, the preparation method further comprises: forming a Si-doped n-type etching stop layer between the n-Al x Ga 1-x N current spreading layer and the stacked AlGaN structure, the Si-doped n-type etching stop layer having a Si doping concentration not higher than a Si doping concentration of the n-Al y Ga 1-y N of the stacked AlGaN structure, and the Si-doped n-type etching stop layer having an Al component content between an Al component content of the n-Al x Ga 1-x N current spreading layer and an Al component content of the stacked AlGaN structure.

[0037] In some embodiments, the preparation method further comprises: depositing an etching barrier layer on the stacked AlGaN structure, the etching barrier layer having an Al component content not higher than an Al component content of the stacked AlGaN structure, and the etching barrier layer being undoped or having a Si doping concentration lower than a Si doping concentration of the n-Al y Ga 1-y N layer of the stacked AlGaN structure.

[0038] In some embodiments, the number of layers of the multilayer n-Al y Ga 1-y N layer is greater than or equal to 4, and the number of layers of the multilayer n-Al + -Al z Ga 1-z N layer is greater than or equal to 3.

[0039] To more clearly illustrate the preparation method of the embodiments of the present disclosure, specific embodiments are provided below for detailed introduction. The present embodiments are described by taking a reflective band center wavelength of 310 nm as an example.

[0040] First, an AlN layer, a 1.6-μm-thick n-Al current spreading layer, and a 0.2-μm-thick p-Al current spreading layer are sequentially deposited on a c-plane sapphire substrate, wherein the n-Al current spreading layer has a Si doping concentration of 5×1018 cm-3.

[0041] Figure 2 A structure schematic diagram of an epitaxial wafer according to an embodiment of the present disclosure is schematically shown.

[0042] As shown in FIG. 1, first, an AlN layer, a 1.6-μm-thick n-Al Figure 2 current spreading layer, and a 0.2-μm-thick p-Al 9 periods of lightly Si-doped layers and heavily Si-doped layers are alternately grown on the current spreading layer, with layer thicknesses of 33 nm and 44 nm respectively, and Si doping concentrations of and respectively; then 3 periods of lightly Si-doped layers and heavily Si-doped layers are alternately grown, with layer thicknesses of 33 nm and 44 nm respectively, and Si doping concentrations of and respectively; finally, 3.5 periods of lightly Si-doped layers and heavily Si-doped layers are alternately grown, with layer thicknesses of 33 nm and 44 nm respectively, and Si doping concentrations of and , i.e. 15.5 periods of stacked structure are deposited on the current spreading layer to obtain an epitaxial wafer.

[0043] It should be understood that the Al composition, layer thickness, Si doping concentration, number of periods of the stacked structure, etc. given in the above steps are only a reference provided by the present embodiment and are not intended to limit the present disclosure.

[0044] wherein, the thicknesses of the layers of the stacked structure are reasonably set according to the DBR reflectivity design principle ( ×d i = / 4, wherein is the center wavelength of the DBR reflection band, is the refractive index of the lightly Si-doped layer and the nano-porous form of the heavily Si-doped layer at the wavelength ) and the required center wavelength. The equivalent refractive index of the functional layer is determined by the porosity after the electrochemical or photoelectrochemical corrosion is completed, and the porosity depends on the Al composition, doping concentration and specific parameters of the corrosion.

[0045] wherein, in the stacked structure, the Si doping concentration of the heavily Si-doped layer is preferably 1.5 times or more of that of the lightly Si-doped layer, so as to ensure that the electrochemical or photoelectrochemical corrosion occurs preferentially in the heavily Si-doped layer, while the lightly Si-doped layer does not corrode.

[0046] wherein, the number of complete periods of the stacked structure is an integer ≥ 3, and the number of periods in the present embodiment is 15.5.

[0047] wherein, ​In the stacked structure, the doping concentration of the heavy Si-doped layer as a whole presents a gradually increasing trend from bottom to top, and the doping concentration of the heavy Si-doped layer can be gradually increased layer by layer, periodically combined to increase, or only increased in several heavy Si-doped layers close to the upper surface.

[0048] wherein, In the stacked structure, the Al component of the heavy Si-doped layer can also gradually decrease from bottom to top to increase the porosity of the heavy Si-doped layer close to the upper surface.

[0049] wherein, in The current spreading layer and Between the stacked structure and The Si-doped n-type etching stop layer has an Al component between the two and a Si doping concentration not higher than The light Si-doped layer in the stacked structure protects the current spreading layer below from etching.

[0050] wherein, in Above the stacked structure, an etching barrier layer can also be deposited, which has an Al component not higher than The Si-doped layer in the stacked structure has a Si doping concentration lower than The light Si-doped layer in the stacked structure or is not doped at all to protect the surface of the epitaxial wafer from etching.

[0051] wherein, in Above the stacked structure, other functional layers such as multiple quantum wells and p-type AlGaN layers can also be deposited, which together form a complete optoelectronic device.

[0052] Figure 3 The structure of the epitaxial wafer with a protective layer formed according to an embodiment of the present disclosure is schematically shown.

[0053] As Figure 3 shown, next, a protective layer is deposited on the surface of the epitaxial wafer where a high-reflectivity DBR region needs to be prepared to avoid longitudinal etching of the epitaxial wafer during electrochemical or photoelectrochemical etching. The protective layer material includes but is not limited to , , photoresist, etc.

[0054] Figure 4 The schematic diagram of removing the protective layer and the stacked AlGaN structure in the preset region of the n-Al x Ga 1-x N current spreading layer according to an embodiment of the present disclosure is schematically shown.

[0055] As Figure 4 shown, next, for the region where a high-reflectivity DBR does not need to be prepared, the All the epitaxial layers above the current spreading layer (or n-type etch stop layer); or using laser scribing, diamond knife grooving and other methods to make The sidewall of the stacked structure is exposed.

[0056] Next, In is coated on the edge of the epitaxial wafer or other metal electrodes are prepared, and the metal electrodes are connected to the anode of the power supply The current spreading layer forms an electrical connection.

[0057] Next, the epitaxial wafer is placed in an electrolyte, and the aforementioned prepared metal electrodes are connected to the anode of the power supply, and the electrolyte is connected to the cathode of the power supply through a platinum sheet or other noble metal electrode. The electrolyte is, for example, , HCl, , , , , , , , solution that does not react with the protective layer in step 3.

[0058] Figure 5 The structure of the epitaxial wafer after electrochemical or photoelectrochemical etching according to an embodiment of the present disclosure is schematically shown. Figure 6 The device for electrochemical etching according to an embodiment of the present disclosure is schematically shown.

[0059] As shown in Figure 5 and Figure 6 , next, the power supply is turned on for electrochemical etching or photoelectrochemical etching, so that The layer forms a nanoporous morphology, the pore size of the nanoporous structure is 1-60 nm; the porosity is 1%-80%; and The morphology of the layer remains unchanged.

[0060] The etching voltage can be 3-100 V. During the etching process, the nanoporous morphology can be adjusted by heating the electrolyte, changing the concentration of the electrolyte, adjusting the etching voltage value and etching time, etc.

[0061] The photoelectrochemical etching method is suitable for the case where the Al component of the heavy Si-doped layer is lower than that of the light Si-doped layer. In this case, the photon energy of the applied ultraviolet light source must be able to be absorbed by the heavy Si-doped layer, but not by the light Si-doped layer.

[0062] After the etching is completed, the epitaxial wafer is taken out, the protective layer on the surface is removed, and the epitaxial wafer is washed clean with deionized water, obtaining a high-reflectivity AlGaN-based DBR with a nanoporous structure.

[0063] Figure 7An example of a reflection spectrum of an AlGaN-based DBR prepared by the preparation method according to the embodiments of the present disclosure is shown schematically.

[0064] As shown in Figure 7 Compared with the conventional preparation method, the nano-porous morphology of the AlGaN-based DBR prepared by the preparation method according to the embodiments of the present disclosure is uniformly distributed from bottom to top, and the peak reflectivity is high.

[0065] The above describes the embodiments of the present disclosure. However, these embodiments are merely for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for fabricating a high-reflectivity AlGaN-based distributed Bragg reflector, characterized in that, Comprise: a stack of AlN layers, n-Al x Ga 1-x N current spreading layers are sequentially deposited on a substrate In the n-Al x Ga 1-x Alternating stacked n-Al layers grown on N-current spreading layers y Ga 1-y N-layer and multi-layer n + -Al z Ga 1-z N layers are formed to create a stacked AlGaN structure, resulting in an epitaxial wafer. + -Al z Ga 1-z Layer N is located in the multilayer n-Al y Ga 1-y Between layers N; depositing a protective layer on the epitaxial wafer and removing n-Al x Ga 1-x N current spreading layer on the predetermined region of the protective layer and the stacked AlGaN structure; The epitaxial wafer with the protective layer is put into an electrolyte, and n-Al x Ga 1-x The n-AlN current spreading layer is connected with the anode of a power supply, and the electrolyte is connected with the cathode of the power supply. controlling electrochemical or photoelectrochemical etching of the epitaxial wafer in an electrolyte to form a nanoporous structure within the n + -Al z Ga 1-z N layer Remove the remaining protective layer to obtain high reflectivity AlGaN-based distributed Bragg reflector.

2. The production method according to claim 1, characterized by, The multi-layer n-Al y Ga 1-y N layer is a lightly Si-doped n-Al y Ga 1-y N; the multi-layer n + -Al z Ga 1-z N layer is a heavily Si-doped n + -Al z Ga 1-z N layer.

3. The method of claim 2, wherein, n-Al y Ga 1-y N layer is directed toward the n + -Al z Ga 1-z Si-doped n + -Al z Ga 1-z Si-doped concentration of the multiple layers of n + -Al z Ga 1-z Si-doped concentration of the n + -Al z Ga 1-z Si-doped concentration of the n + -Al z Ga 1-z Si-doped concentration of the n + -Al z Ga 1-z Si-doped concentration of the n y -Al 1-y Ga Si-doped concentration of the n 4. The production method according to claim 2, characterized by, The n-Al x Ga 1-x The content of the A1 component of the n-Al y Ga 1-y The content of the A1 component of the n-Al y Ga 1-y The content of the A1 component of the n-Al + -Al z Ga 1-z The content of the A1 component of the n-Al 5. The preparation method according to claim 2, characterized in that, along the n-Al y Ga 1-y N layer points in the direction of the n + -Al z Ga 1-z Si-doped n + -Al z Ga 1-z N layer, the content of Al component gradually decreases in the multi-layer.

6. The method of any one of claims 1 to 5, wherein the method further comprises the step of: The multilayer n-Al y Ga 1-y N layer and the multilayer n + -Al z Ga 1-z N layer each satisfy n i x d i = λ0 / 4, where λ0is a center wavelength, n i is the refractive index of the n-Al y Ga 1-y N layer and the nanoporous n + -Al z Ga 1-z N layer at the wavelength λ0.

7. The method of any one of claims 1 to 5, wherein the method further comprises the step of: By adjusting the corrosion conditions of electrochemical corrosion or photoelectrochemical corrosion, n + -Al z Ga 1-z A nanoporous structure having a pore diameter of 1 nm to 60 nm and a porosity of 1 to 80% is formed inside the GaN layer. ​ 8. The preparation method according to claim 2, characterized in that, Also include: In the n-Al x Ga 1-x N current spreading layer, a Si-doped n-type etch-stop layer is formed between the stacked AlGaN structure and the n-Al y Ga 1-y N current spreading layer, a Si-doped n-type etch-stop layer is formed between the stacked AlGaN structure and the n-Al x Ga 1-x N current spreading layer, a Si-doped n-type etch-stop layer is formed between the stacked AlGaN structure and the n-Al And / or, depositing an etch stop layer on the stacked AlGaN structure, the etch stop layer having an Al composition content no higher than the Al composition content of the stacked AlGaN structure, the etch stop layer being either undoped or having a Si doping concentration lower than the light Si doping of the stacked AlGaN structure n-Al y Ga 1-y N layer.

9. The method of claim 1, wherein, The multilayer n-Al y Ga 1-y The number of layers of the multilayer n + -Al z Ga 1-z The number of layers of the multilayer n 10. The method of claim 1, wherein, The electrolyte includes acidic electrolyte, alkaline electrolyte and at least one of acidic electrolyte, alkaline electrolyte, and the corrosion voltage used for electrochemical corrosion or photoelectrochemical corrosion can be 3V~100V; the morphology of the nanoporous structure is adjusted by at least one of heating the electrolyte, changing the concentration of the electrolyte, adjusting the corrosion voltage value and the corrosion time.

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