A silicon-based reflection interference sensor for selectively detecting molecules and a preparation method thereof

Abstract

The present invention belongs to the field of optical sensing technology, and proposes a silicon-based optical sensor based on reflection interference spectroscopy technology and a preparation method, which includes an ordered silicon nanowire array layer, a disordered porous silicon layer, and a planar silicon substrate in sequence along the incident direction of the composite light; each nanowire is provided with randomly distributed nanopores; the disordered porous silicon layer is located below the ordered silicon nanowire array layer, and the layer is provided with nanopores randomly distributed in a dendrite shape. When used for reflection interference sensing testing, small molecules can penetrate into the disordered porous silicon layer, while target small molecules and interfering macromolecules can simultaneously penetrate into the ordered silicon nanowire array layer; compared with a double-layer disordered porous silicon structure, this solution not only significantly enhances the fluidity of the test liquid and the sensitivity of the sensor, but also reduces the response time; compared with a single-layer ordered silicon nanowire array structure or a single-layer disordered porous silicon structure, it has the advantage of simultaneously detecting target small molecules and interfering macromolecules.

Description

Technical Field

[0001] The invention belongs to the technical field of optical sensing and relates to the design and preparation of a silicon micro-nano structure for a reflection interference sensor. Background Art

[0002] Reflection interference optical sensors are based on the interaction between light waves (or passing through a medium) and the substance to be tested. The change in optical properties causes the change in the reflection interference spectrum, and then inverts the concentration or type of the substance to be tested. It has extremely wide applications in the fields of drug delivery, medical diagnosis, environmental monitoring, food safety, and gene sequencing. The detection of biological / chemical molecules, including the detection of harmful molecules / ions, is increasingly moving towards real-time, rapid, low detection limit, and wide detection range.

[0003] At present, the optical sensing technologies for biological / chemical molecule detection at home and abroad can be roughly divided into three types, namely fluorescence spectroscopy, surface plasmon resonance (SPR) and reflection interference spectroscopy. Among them, fluorescence spectroscopy is easily interfered by probe fluorescence quenching or autofluorescence; SPR technology has poor ability to selectively detect biological / chemical molecules in complex environments and lacks real-time performance; while reflection interference spectroscopy sensors have the advantages of low detection limit, high sensitivity, good real-time performance, and wide detection concentration range. At present, reflection interference optical sensors are mainly based on porous materials (such as porous silicon, porous aluminum oxide, porous titanium oxide, etc.), among which the research on optical sensors based on porous silicon is the most extensive. However, this type of sensor has obvious disadvantages. The main reason is that the preparation method of porous materials is usually electrochemical anodic corrosion method, and the diameter of the nanopores prepared is small and the adjustable range is small, thereby limiting the range of sensing substances; in addition, the substance to be tested does not flow smoothly in the semi-closed nanopores, which will affect the response time and sensitivity of the sensor, and the interfering molecules are easy to block the nanopores, and the more unfavorable effects are shown as the thickness of the porous layer increases. To address the problem that this type of sensor cannot achieve selective detection of target molecules in a complex environment, the usual approach is to modify the probe molecules (i.e., sensitive elements) on the porous surface. However, due to the inherent hysteresis effect of the sensitive mechanism, the sensor is susceptible to external interference, thereby reducing the sensing sensitivity. Summary of the invention

[0004] The present invention aims to solve the problems of the conventional reflective interference sensor based on porous materials in the prior art, which cannot selectively detect the target molecules, has a limited detection range, and has a long response time due to the random distribution and uneven size of the pore size of the porous materials and the semi-closed nanopores. The technical solution adopted is as follows:

[0005] A silicon-based optical sensor based on reflection interference spectroscopy technology, wherein the silicon base is a hybrid structure, and includes an ordered silicon nanowire array layer, a disordered porous silicon layer, and a planar silicon substrate in sequence along the incident direction of composite light; wherein the ordered silicon nanowire array is formed by a periodic arrangement of non-solid nanowires, and each nanowire is provided with randomly distributed nanopores; the disordered porous silicon layer is located below the ordered silicon nanowire array layer, and the layer is provided with nanopores randomly distributed in a dendrite shape, and the maximum diameter of the nanopores is smaller than the diameter of the nanowires and the minimum spacing; the planar silicon substrate is a solid structure, and is located below the disordered porous silicon layer.

[0006] A method for preparing a silicon-based optical sensor based on reflection interference spectroscopy technology, wherein an ordered silicon nanowire array layer is prepared on a planar silicon substrate of a solid structure by photolithography technology and wet etching or dry etching silicon technology; the diameter, spacing and period of the ordered silicon nanowires are controlled by parameters in the photolithography process, and the length of the ordered silicon nanowires is controlled by parameters in the wet etching or dry etching silicon process; with the composite structure of the ordered silicon nanowire array / planar silicon substrate as the substrate, randomly distributed nanopores are prepared inside each nanowire by electrochemical anodic etching of silicon, and nanopores randomly distributed in the form of dendrites are prepared on one side of the contact surface between the planar silicon substrate and the ordered silicon nanowire array; the area on the planar silicon substrate where the nanopores randomly distributed in the form of dendrites are etched by the electrochemical anodic etching is the disordered porous silicon layer, and the diameter and length of the nanopores are controlled by parameters in the electrochemical anodic etching silicon process; after the ordered silicon nanowires are electrochemically anodic etched, the nanowires are changed from the original solid structure to a porous structure, and nanopores randomly distributed in the form of dendrites are introduced into the interior of a single nanowire, but the diameter, spacing and period of the nanowires remain unchanged. The area on the planar silicon substrate where the nanopores randomly distributed in a dendrite shape are etched by the electrochemical anode changes from the original solid structure to a porous structure. This area is the disordered porous silicon layer, and the part of the planar silicon substrate that is not etched by the electrochemical anode is still a solid structure. There is no obvious difference in diameter, distribution and morphology between the nanopores in the disordered porous silicon layer and the nanopores in the ordered silicon nanowires after electrochemical anode corrosion; all the nanopores constitute a microtubule channel with a dendrite distribution.

[0007] In the scheme of the present invention, when the reflection interference sensor of the silicon-based hybrid structure detects the target small molecules, since the nanowires in the ordered silicon nanowire array layer can ensure that all molecules flow smoothly in the layer, and only small molecules can enter the microtubule channels with dendritic distribution, the equivalent refractive index of the ordered silicon nanowire array layer contains the information of the target small molecules and the interfering macromolecules, while the equivalent refractive index of the disordered porous silicon layer only contains the information of the target small molecules. The reflection interference spectrum is processed by fast Fourier transform (FFT), and the displacement of different characteristic peaks corresponds to the change of the equivalent refractive index of different structural layers. Compared with the double-layer disordered porous silicon structure, the silicon-based hybrid structure designed by the scheme of the present invention not only significantly enhances the fluidity of the test liquid and the sensor sensitivity, but also reduces the response time; compared with the single-layer ordered silicon nanowire array structure (or single-layer disordered porous silicon nanostructure), it has the advantage of simultaneously detecting the target small molecules and interfering macromolecules.

[0008] For the silicon-based hybrid structure, the incident composite light can generate reflection signals on the surface of the ordered silicon nanowire array layer, the interface between the ordered silicon nanowire array layer and the porous silicon layer, and the interface between the porous silicon layer and the planar silicon substrate. The corresponding reflected lights at different interfaces or surfaces interfere with each other to form reflection interference fringes. The intensity of the obtained reflection interference signal and the wavelength of the interference peak are related to the thickness and equivalent refractive index of the ordered silicon nanowire array layer and the disordered porous silicon layer. Three characteristic peaks can be obtained through FFT processing. By analyzing the movement of these three characteristic peaks, the equivalent refractive index changes of the ordered silicon nanowire array layer and the disordered porous silicon layer can be inverted.

[0009] In the above scheme: the spacing of nanowires in the ordered silicon nanowire array layer is 20nm to 10μm, and the size of nanopores in the disordered porous silicon layer is 2nm to 20nm. Preferably, the thickness of the ordered silicon nanowire array layer is 500nm to 10μm, the silicon nanowire array is arranged in a hexagonal or tetragonal pattern, the nanowire diameter is 100nm to 2000nm, and the minimum spacing between adjacent silicon nanowires is 50nm to 4000nm.

[0010] Preferably, the disordered porous silicon layer has a thickness of 100 nm to 50 μm and a porosity of 30% to 90%.

[0011] Preferably, the spacing between nanowires in the ordered silicon nanowire array layer and the diameter of the nanopores in the disordered porous silicon layer are designed and prepared according to the sizes of the target molecules and the interfering molecules.

[0012] Preferably, the planar silicon substrate is p-type doped, has a resistivity of 0.001 to 100 Ω·cm, and a thickness of 20 μm to 1000 μm.

[0013] The present application also discloses a method for preparing a silicon-based hybrid structure for a reflective interference optical sensor, comprising:

[0014] A single-sided polished p-type single crystal silicon is selected on a planar silicon substrate of a solid structure, and a single layer of densely packed polystyrene balls is self-assembled on the polished surface; the polystyrene balls are reduced by plasma etching technology, and their diameter is changed to 30% to 90% of the original value; a layer of 2 to 5 nm titanium is first deposited by electron beam evaporation technology, and then a layer of 20 to 50 nm gold is deposited; the polystyrene balls are removed; a silicon nanowire array is prepared by metal-assisted chemical etching silicon technology; the residual titanium / gold film is removed to obtain an ordered silicon nanowire array layer; electrochemical anodic etching is performed on the composite structure of the ordered silicon nanowire array / planar silicon substrate as the substrate; the sample after the electrochemical anodic etching is cleaned and dried to obtain an ordered silicon nanowire array layer / disordered porous silicon layer structure on the planar silicon substrate; thermal oxidation treatment is performed in air, the heat treatment temperature is 500 to 900° C., and the treatment time is 0.2 to 2 hours.

[0015] Technical Effects

[0016] By adopting the solution of the present technical invention, the period, diameter, spacing and thickness of the ordered silicon nanowire array layer can be precisely controlled within the range of 20nm to 10μm, which has a significant enhancement effect on the circulation of the test liquid containing target molecules and interfering molecules in the porous structure, and is a prerequisite for realizing the selective testing of target small molecules and the rapid detection of interfering macromolecules. In addition, the diameter of the porous nanostructure of the disordered porous silicon layer prepared by subsequent electrochemical anodic corrosion can only vary within the range of 2nm to 20nm, and the overall size is much smaller than the diameter and spacing of the ordered silicon nanowires, which can ensure that the target small molecules enter the porous layer, while the interfering macromolecules cannot. By adopting this technical solution, it can also be ensured that when preparing the disordered porous silicon layer, the overall structure of the previously prepared ordered silicon nanowire array layer is not destroyed, that is, the integrity and independence of the hybrid structure of the ordered silicon nanowire array layer / disordered porous silicon layer are realized. When the hybrid structure prepared by the scheme of the present invention is used for reflection interference sensing test, only small molecules can penetrate into the bottom layer of the hybrid structure (i.e., disordered porous silicon layer), while the target small molecules and interfering macromolecules can simultaneously penetrate into the top layer of the hybrid structure (i.e., ordered silicon nanowire array layer). The reflection interference spectrum is processed by FFT, and the displacement of different characteristic peaks corresponds to the change of the equivalent refractive index of different structural layers. Through data processing and analysis, the concentration of the target small molecule and the interfering macromolecule can be quantitatively calculated. In contrast, the double-layer disordered porous silicon nanostructure has a small range of nanopore size variation and poor uniformity of the top layer of disordered silicon, which makes the nanopores easily blocked by interfering molecules and the penetration of target molecules is blocked; and for the single-layer disordered porous silicon structure or the single-layer ordered silicon nanowire array structure, since the interfering macromolecules cannot penetrate into the nanopores or the large and small molecules simultaneously penetrate into the interval of the ordered silicon nanowires, the macromolecules and small molecules cannot be selectively or simultaneously detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : Schematic diagram of silicon-based hybrid structure and principle diagram of reflection interference;

[0018] Wherein: 10 is the incident composite light, 11 is the light reflected by the surface of the ordered silicon nanowire array layer (i.e., interface 1), 12 is the light reflected by the ordered silicon nanowire array / disordered porous silicon interface (i.e., interface 2), 13 is the light reflected by the disordered porous silicon / planar silicon substrate interface (i.e., interface 3), 14 is the ordered silicon nanowire array layer, 15 is the porous silicon layer, and 16 is the planar silicon substrate.

[0019] Figure 2 : Typical reflection interference spectrum of silicon-based hybrid structure in glucose solution.

[0020] Figure 3 : Typical FFT spectra of silicon-based hybrid structures in glucose solution;

[0021] Among them, 31 is FFT characteristic peak 1, 32 is FFT characteristic peak 2, and 33 is FFT characteristic peak 3.

[0022] Figure 4 :Electron microscopy image of a cross section of an ordered silicon nanowire array;

[0023] Among them, 41 are single-layer ordered silicon nanowire arrays.

[0024] Figure 5 : Top surface electron microscopy image of ordered silicon nanowire arrays.

[0025] Figure 6 : Cross-sectional scanning electron microscopy image of the silicon-based hybrid structure;

[0026] The magnification effect of the black box area is as follows: Figure 7 .

[0027] Figure 7 : High-magnification electron microscope image of the bottom of the silicon-based hybrid structure.

[0028] Figure 8 : High-magnification electron microscopy image of the top surface of the silicon-based hybrid structure;

[0029] The white area corresponds to the top of a single nanowire, and the black area is the gap at the bottom of the nanowire.

[0030] Fig. 9 :Schematic diagram of the reflection interference optical sensing system of silicon-based hybrid structure;

[0031] Among them, 91 is a light source, 92 is a Y-type optical fiber, 93 is a fiber optic spectrometer, 94 is a micro booster; 95 is a computer system, 96 is a liquid conduit, and 97 is a silicon-based hybrid structure.

[0032] Fig.10 : Real-time test data of the reflection interference sensor of silicon-based hybrid structure in different solutions;

[0033] Among them, 101-103 correspond to FFT characteristic peaks 1-3 respectively; I-VIII represent PBS buffer, 30 mg / mL bovine serum albumin solution, 50 mg / mL bovine serum albumin solution, 50 mg / mL glucose, 100 mg / mL glucose, 50 mg / mL glucose + 30 mg / mL bovine serum albumin solution, 50 mg / mL glucose + 50 mg / ml bovine serum albumin solution and 30 mg / mL bovine serum albumin solution + 100 mg / mL glucose respectively.

[0034] Fig.11 :Comparison of sensitivity of glucose sensing by reflection interferometry sensors based on different silicon nanostructures;

[0035] Among them, 111 corresponds to the hybrid structure of ordered silicon nanowire array / disordered porous silicon, and 112 corresponds to the double-layer porous silicon structure.

[0036] Fig.12 : Schematic diagram of the structure of double-layer disordered porous silicon;

[0037] 121 is a top porous silicon structure with a larger porosity, and 122 is a bottom porous silicon structure with a smaller porosity.

[0038] Fig.13 : Schematic diagram of the structure of a single layer of disordered porous silicon;

[0039] Among them, 131 is a single-layer porous silicon structure. DETAILED DESCRIPTION

[0040] In order to more clearly illustrate the present technical solution, further description is given below in conjunction with the accompanying drawings and embodiments.

[0041] Embodiment 1

[0042] A silicon-based reflective interference sensor for selectively detecting molecules, the main structure of which is a hybrid structure of an ordered silicon nanowire array layer / disordered porous silicon layer. Figure 1 As shown, along the incident direction of the composite light 10, the ordered silicon nanowire array layer 14, the disordered porous silicon layer 15, and the planar silicon substrate 16 are included in sequence; the gaps between the ordered nanowires and the pores of the porous silicon are filled with the test liquid, and the target small molecules and interfering macromolecules contained in the test liquid can flow in the gaps between the ordered nanowires, while only the target small molecules can penetrate into the pores of the porous silicon layer. Due to the immersion of the test liquid containing the target small molecules and the interfering macromolecules, the equivalent refractive index of the ordered silicon nanowire array layer and the disordered porous layer silicon changes, and the amount of change is closely related to the concentration of the target small molecules and the interfering macromolecules. When the composite light is incident almost vertically on the hybrid structure of the ordered silicon nanowire array layer / disordered porous silicon layer immersed in the test liquid, a reflected light 11 is formed on the surface of the ordered silicon nanowire array layer (i.e., interface 1), a reflected light 12 is formed when passing through the interface 2 of the ordered silicon nanowire array layer / disordered porous silicon layer, and a reflected light 13 is formed when passing through the interface 3 of the disordered porous silicon layer / silicon substrate. These reflected lights interfere with each other, and a spectrometer is used to collect and observe the reflection interference spectrum. Typical results are shown in FIG. Figure 2 After FFT processing, an FFT spectrum containing three characteristic peaks can be obtained, as shown in Figure 3 As shown, 31 (characteristic peak 1) corresponds to Figure 1 The interference effect formed by the light reflected from interface 1 and interface 2; 32 (characteristic peak 2) corresponds to Figure 1 The interference effect formed by the light reflected from interface 2 and interface 3; 33 (characteristic peak 3) corresponds to Figure 1The interference effect formed by the light reflected from interface 1 and interface 3. By analyzing the displacement of these three FFT characteristic peaks, the concentrations of target small molecules and interfering macromolecules contained in the test solution can be inverted.

[0043] Embodiment 2

[0044] A method for preparing an ordered silicon nanowire array / disordered porous silicon hybrid structure for a reflection interference sensor, the preparation steps comprising:

[0045] 1) A single-sided polished p-type single crystal silicon substrate is used as a substrate, which is cleaned and then a layer of close-packed polystyrene (PS) spheres are self-assembled on the polished surface, with an original diameter of 1000 nm;

[0046] 2) The PS balls were etched using inductively coupled plasma etching technology, and the diameter of the PS balls after etching was 400 nm;

[0047] 3) Using an electron beam evaporation system, a 5 nm Ti layer is first deposited, followed by a 40 nm Au layer;

[0048] 4) Ultrasonic cleaning in tetrahydrofuran, chloroform, ethanol and deionized water for 15 min each to remove PS spheres;

[0049] 5) chemically corroding the sample obtained in step 4) using a mixed solution of hydrofluoric acid and hydrogen peroxide as an etching solution;

[0050] 6) Use a mixture of hydrochloric acid and nitric acid to remove the remaining Ti / Au film to obtain Figure 4 (cross section) and 5 (top view) of the ordered silicon nanowire array;

[0051] 7) Taking the ordered silicon nanowire array silicon as the electrochemical corrosion substrate, a layer of indium gallium is coated on the back thereof, and the ordered silicon nanowire array silicon substrate is electrochemically anodic-corroded, the etching liquid is a mixture of hydrofluoric acid and ethanol, the corrosion current is 150 mA, and the corrosion time is 40 s;

[0052] 8) The sample after electrochemical corrosion is cleaned and dried to obtain a hybrid structure of ordered silicon nanowire array layer / disordered porous silicon layer. The microstructure is as follows Figures 6 to 8 As shown;

[0053] A reflection interference sensing system is constructed by combining a light source 91 (e.g., Ocean Optics halogen lamp, HL2000), a Y-type optical fiber 92 (e.g., Ocean Optics, QR600-7-SR-125F), an optical fiber spectrometer 93 (e.g., Ocean Optics, USB4000), a micro booster 94, a computer 95, a liquid conduit 96 and a sensor main structure 97. Fig. 9Phosphate (PBS) buffer was used as the background solution, and different concentrations of glucose molecules and bovine serum albumin molecules were mixed in, which served as the sensing target molecules and interfering macromolecules, respectively.

[0054] Bovine serum albumin molecules can enter the ordered silicon nanowire array layer but not the porous silicon layer, while glucose molecules can enter both the ordered silicon nanowire array layer and the disordered porous silicon layer, causing the refractive index of the corresponding layers to change differently, as shown by the change in the position of the FFT characteristic peak (i.e., 2 times the effective optical thickness). The three characteristic peaks corresponding to the hybrid structure correspond to Figure 1 The result of interference between the reflected light formed by interfaces 1 and 2, interfaces 2 and 3, and interfaces 1 and 3. Fig.10 It can be seen that when the solution is 30mg / mL and 50mg / mL bovine serum protein solution (II and III), compared with PBS buffer I, the position of FFT characteristic peak 2 corresponding to the underlying porous silicon structure has not changed; at the same time, taking PBS buffer I as the baseline, 50mg / ml glucose IV, 50mg / mL glucose + 30mg / mL bovine serum protein solution VI and 50mg / mL glucose + 50mg / mL bovine serum protein solution VII are compared as a group, that is, keeping the glucose concentration unchanged and changing the bovine serum protein solution concentration in turn, the position of FFT characteristic peak 2 hardly moves, and the positions of FFT characteristic peaks 1 and 3 both shift to the right as the concentration of the bovine serum protein solution increases. It can be concluded that in a complex environment, the sensing target small molecules can enter the ordered silicon nanowire array and the porous silicon layer at the same time, while the interfering macromolecules can only enter the ordered silicon nanowire array and cannot enter the porous silicon layer, so the sensor can selectively detect the concentration of the molecules to be measured. Similarly, the same conclusion can be obtained by keeping the concentration of bovine serum albumin solution unchanged and changing the glucose concentration in sequence, that is, taking PBS buffer I as the baseline and selecting II, VI and VIII as a group for analysis.

[0055] Furthermore, the hybrid structure can realize real-time and selective testing of glucose concentration in a mixed solution of bovine serum albumin (30 mg / mL) and glucose of different concentrations (2 mmol / L to 5 mol / L). Fig.11 As shown in Figure 2, the hybrid structure maintains a linear response in the concentration range of 2mmol / L to 3mol / L, and can produce a response of 303.7nm under a concentration change of 1M. Fig.12 The sensor can only produce a displacement of 191.7nm. The hybrid structure prepared by the scheme of the present invention is similar to the double-layer disordered porous silicon structure (schematic diagram as shown in Fig.12Compared with the single-layer ordered silicon nanowire array structure (typical structure as shown in Figure 4 and 5 As shown) or a single layer disordered porous silicon structure (schematic diagram as shown Fig.13 Compared with the hybrid structure shown in Figure 2, the proposed optical sensor based on the hybrid structure has the function of selectively detecting molecules.

[0056] Furthermore, if the prepared hybrid structure is subjected to appropriate thermal oxidation treatment, a dense silicon oxide layer can be formed on the surface of the silicon nanostructure, which can significantly improve the performance stability of silicon-based optical sensors. In addition, the optical sensing sensitivity can be further improved by performing appropriate pore expansion treatment on the porous structure (such as repeated thermal oxidation treatment and deoxidation layer treatment).

Claims

1. A silicon-based optical sensor based on reflection interference spectroscopy technology, wherein the silicon-based optical sensor is a hybrid structure, characterized in that: The invention comprises an ordered silicon nanowire array layer, a disordered porous silicon layer and a planar silicon substrate in sequence along the incident direction of the composite light; wherein the ordered silicon nanowire array is formed by a periodic arrangement of non-solid nanowires, and each nanowire is provided with randomly distributed nanopores; the disordered porous silicon layer is located below the ordered silicon nanowire array layer, and the layer is provided with nanopores randomly distributed in a dendrite shape, and the maximum diameter of the nanopores is smaller than the diameter and the minimum spacing of the nanowires; the planar silicon substrate is a solid structure, and is located below the disordered porous silicon layer; the spacing between the nanowires in the ordered silicon nanowire array layer and the diameter of the nanopores in the disordered porous silicon layer are designed and prepared according to the sizes of the target molecules and the interfering molecules.

2. A silicon-based optical sensor based on reflection interference spectroscopy technology according to claim 1, characterized in that: The interval between nanowires in the ordered silicon nanowire array layer is 20nm-10μm, and the size of nanopores in the disordered porous silicon layer is 2nm-20nm.

3. A silicon-based optical sensor based on reflection interference spectroscopy technology according to claim 2, characterized in that: The interval between adjacent silicon nanowires is 50nm to 4000nm.

4. A silicon-based optical sensor based on reflection interference spectroscopy technology according to claim 1, characterized in that: The ordered silicon nanowire array layer has a thickness of 500nm to 10μm, the silicon nanowire array is arranged in a hexagonal or tetragonal pattern, and the diameter of the nanowire is 100nm to 2000nm.

5. A silicon-based optical sensor based on reflection interference spectroscopy technology according to claim 1, characterized in that: The disordered porous silicon layer has a thickness of 100nm to 50μm and a porosity of 30% to 90%.

6. A silicon-based optical sensor based on reflection interference spectroscopy technology according to claim 1, characterized in that: The planar silicon substrate is p-type doped, has a resistivity of 0.001-100Ω·cm, and a thickness of 20μm-1000μm.

7. A method for preparing a silicon-based optical sensor based on reflection interference spectroscopy technology, characterized in that: An ordered silicon nanowire array layer is prepared on a planar silicon substrate of a solid structure by photolithography technology and wet or dry etching silicon technology; the diameter, spacing and period of the ordered silicon nanowires are controlled by parameters in the photolithography process, and the length of the ordered silicon nanowires is controlled by parameters in the wet or dry etching silicon process; with the composite structure of ordered silicon nanowire array / planar silicon substrate as the substrate, randomly distributed nanopores are prepared inside each nanowire by electrochemical anodic etching of silicon, and nanopores randomly distributed in a dendrite shape are prepared on the side of the contact surface with the ordered silicon nanowire array on the planar silicon substrate; the area on the planar silicon substrate where the nanopores randomly distributed in a dendrite shape are etched by the electrochemical anodic etching is the disordered porous silicon layer, and the diameter and length of the nanopores are controlled by parameters in the electrochemical anodic etching silicon process; after the ordered silicon nanowires are electrochemically anodic etched, the diameter, spacing and period of the nanowires remain unchanged.

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