A silicon-based near-infrared photosensitive material co-doped with S and Se based on picosecond laser-ion implantation, a preparation method and application thereof

Abstract

The application discloses a kind of S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation and preparation method and application, belong to semiconductor optoelectronic material technical field;A kind of S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation preparation method, comprising the following steps: using vacuum deposition process is deposited Se doped film on the surface of silicon substrate, then by picosecond laser scanning preparation obtains the micro-nano composite structure black silicon;Sulfur ion implantation modification is carried out to the micro-nano composite structure black silicon, annealing, and the S, Se co-doped silicon-based near-infrared photosensitive material is prepared.The application is successfully solved the problem of thermal damage and lattice defect in traditional doping method by the composite doping process of picosecond laser-ion implantation, realizes the preparation of S, Se co-doped silicon-based near-infrared photosensitive material with high concentration and low defect.The light absorption rate of the material at 1300nm band is significantly improved, which provides a mass production process scheme for the third generation photovoltaic device and high-performance infrared detector, and has important application value and broad market prospect.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor optoelectronic materials technology, and particularly relates to an S, Se co-doped silicon-based near-infrared photosensitive material based on picosecond laser-ion implantation, its preparation method, and its application. Background Technology

[0002] Silicon-based optoelectronic materials have core application value in the fields of photodetectors and solar cells, but their intrinsic bandgap (1.12 eV) limits their light absorption efficiency in the near-infrared band (>1100 nm). In recent years, doping with chalcogenide elements (S, Se, Te) has been shown to extend the spectral response range of silicon by introducing intermediate energy levels. Selenium (Se) can lower the bandgap to 0.8-1.0 eV, while sulfur (S) forms deep-level defect states that enhance subband absorption. Current technologies mainly rely on ultrashort laser pulse radiation (such as femtosecond laser instantaneous melting of Se films and silicon surfaces, causing the dopant element Se to diffuse into the crystal lattice) or high-energy ion implantation (such as S...). + While single-element doping can be achieved through laser injection, traditional laser doping suffers from decreased carrier mobility due to thermal damage and is limited by the thermal diffusion effect caused by femtosecond pulse width, resulting in uneven distribution of doped elements and severe surface amorphization. On the other hand, the cascade collision effect of ion implantation can cause irreversible lattice damage, requiring high-temperature annealing. It is difficult to achieve both high doping concentration and low defect density in both doping processes. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a picosecond laser-ion implantation-based S / Se co-doped silicon-based near-infrared photosensitive material, its preparation method, and its applications. It solves the problem of coexisting thermal damage and lattice defects in traditional femtosecond laser and ion implantation single doping methods, achieving the preparation of high-concentration, low-defect silicon-based near-infrared photosensitive materials. Furthermore, through the synergistic effect of Se bandgap modulation and S deep-level defects, the light absorption rate in the 1300nm band is increased to ≥80%, providing a mass-producible process solution for third-generation photovoltaic devices and high-performance infrared detectors.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for preparing S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation includes the following steps:

[0006] A Se-doped thin film was deposited on the surface of a silicon substrate using a vacuum deposition process, and then a black silicon with a micro-nano composite structure was prepared by picosecond laser scanning.

[0007] The black silicon with the micro-nano composite structure was modified by sulfur ion implantation and annealed to prepare the S, Se co-doped silicon-based near-infrared photosensitive material.

[0008] Beneficial Effects: This invention discloses a cascade doping method of "laser scanning followed by ion implantation": Se is doped into a transient molten layer on the silicon surface by picosecond laser, followed by S ion doping using high-energy ion implantation, ultimately achieving S and Se co-doping. The preparation process of this invention has the following significant advantages:

[0009] 1. Improve near-infrared light absorption rate

[0010] The synergistic effect of Se bandgap tuning and S deep-level defects enables the prepared material to achieve a light absorption rate of ≥80% in the 1300nm band. This provides efficient light absorption capability for third-generation photovoltaic devices and high-performance infrared detectors.

[0011] 2. Optimize the doping process to reduce thermal damage and lattice defects.

[0012] Under the picosecond laser processing conditions defined in this invention, efficient doping can be achieved without causing severe thermal damage. By using defined picosecond laser processing parameters and high-energy ion implantation technology, thermal damage and surface amorphization are reduced, and carrier mobility is improved. Combined with subsequent high-temperature annealing, lattice damage that may occur during the doping process is effectively repaired, further improving the crystal quality and photoelectric properties of the material.

[0013] This invention successfully solves the problems of thermal damage and lattice defects in traditional doping methods through a picosecond laser-ion implantation composite doping process, and realizes the preparation of high-concentration, low-defect S and Se co-doped silicon-based near-infrared photosensitive materials.

[0014] Optionally, the silicon substrate is an 8-inch low-resistivity silicon wafer with an N-type (100) crystal orientation, a resistivity of 8 to 10 Ω·cm, and a thickness of 500 ± 25 μm.

[0015] Optionally, the silicon substrate needs to be cleaned before use, and the specific steps are as follows:

[0016] (1) First, pour an appropriate amount of acetone into a clean beaker, place the silicon wafer holder containing the silicon wafer in the beaker, and ensure that the acetone solution completely covers the silicon wafer. Then, place the beaker into an ultrasonic cleaner and clean for 15 minutes. The main purpose of this step is to remove organic contaminants from the surface of the silicon wafer.

[0017] (2) After ultrasonic cleaning, remove the beaker and transfer the silicon wafer to another clean beaker containing an appropriate amount of anhydrous ethanol. Repeat the above steps and ultrasonically clean for another 15 minutes. This process aims to remove acetone residue and inorganic contaminants from the surface of the silicon wafer.

[0018] (3) Finally, place the silicon wafer in a clean beaker containing an appropriate amount of deionized water and ultrasonically clean it for 15 minutes to remove any residual ethanol from the sample surface. After cleaning, remove the silicon wafer, dry its surface with a nitrogen gun, and then place it in a petri dish for later use.

[0019] Optionally, the specific operation of the vacuum deposition process is as follows:

[0020] A silicon substrate was fixed in a vacuum chamber by loading 99.999% pure Se powder onto a tungsten evaporation boat. The vacuum level was then reduced to 8.5 × 10⁻⁶ using a combination of mechanical and molecular pumps. -4 Pa, then a current of 17 ± 0.5 A is applied to... Se-doped films were deposited by evaporation at a certain rate.

[0021] Furthermore, the thickness of the Se-doped film is 250±20 nm.

[0022] Beneficial effects: This invention prepares a 250±20nm thick Se film by vacuum thermal evaporation deposition, ensuring sufficient doping concentration and avoiding the problem of insufficient doping caused by the film being too thin.

[0023] Optionally, the picosecond laser scanning uses a picosecond laser system, which includes:

[0024] The laser source unit includes a sealed laser head (picosecond laser);

[0025] The optical transmission unit includes a reflector, a beam expander, a dichroic mirror, a digital galvanometer scanning device, and a telecentric lens with f=100mm; wherein the digital galvanometer scanning device includes an X-axis galvanometer and a Y-axis galvanometer.

[0026] Two-dimensional mobile platform unit, including micromachining platform;

[0027] Control unit, including console.

[0028] Optionally, the conditions during the picosecond laser scanning process are:

[0029] The laser has a single-pulse energy of 4.5 ± 0.5 μJ, a pulse width of 8.7 ± 0.3 ps, a wavelength of 1064 nm, a spot diameter of 20 μm, a frequency of 2000 kHz, and an average laser pulse energy density of 1.4 ± 0.2 kJ / m². 2 The scanning interval is 10±1μm, the scanning speed is set to 100mm / s, and the number of laser pulses received per unit area is N=400±10.

[0030] Beneficial effects: This invention sets the laser energy density to 1.4 ± 0.2 kJ / m². 2The optimal plasma plume generation window was determined, and combined with the grid scanning mode, uniform molten pool continuity and uniform distribution of doped elements were achieved, avoiding the non-uniformity of the traditional spiral scanning mode. The scanning interval was set to 10±1μm, ensuring molten pool continuity with an overlap rate of more than 85%, which further improved the uniformity and consistency of doping.

[0031] Optionally, the conditions for sulfur ion implantation modification are as follows:

[0032] The single charge state (S) + Ion beam in vacuum greater than 5×10 -4 In a target chamber environment with a target energy of 100 keV (with an allowable error of ±5%), the micro-nano composite structure was vertically injected into the black silicon surface at an incident energy of 3 × 10⁻⁶ Pa. 16 ions / cm 2 (±3% fluctuation allowed).

[0033] Optionally, the annealing conditions are as follows: heating to 700°C at a heating rate of 5°C / min, and then annealing at this temperature for 30 min.

[0034] Beneficial effects: Annealing at 700℃ for 30 minutes effectively repairs lattice damage that may occur during doping, further improving the crystal quality and photoelectric properties of the material.

[0035] Furthermore, the annealing atmosphere is nitrogen (high-purity N2 (O2 content <1ppm), which can prevent selenide oxidation), and the flow rate of the nitrogen is 1.5L / min.

[0036] A picosecond laser-ion implantation-based S, Se co-doped silicon-based near-infrared photosensitive material was prepared by the above-mentioned method.

[0037] The above-mentioned applications of S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation in the fabrication of photovoltaic devices and high-sensitivity infrared detectors.

[0038] Compared with the prior art, the present invention has the following advantages and technical effects:

[0039] This invention successfully solves the problems of thermal damage and lattice defects in traditional doping methods through a picosecond laser-ion implantation composite doping process, achieving the fabrication of high-concentration, low-defect S / Se co-doped silicon-based near-infrared photosensitive materials. The material exhibits significantly improved light absorption in the 1300nm wavelength band, providing a mass-producible process solution for third-generation photovoltaic devices and high-performance infrared detectors, demonstrating significant application value and broad market prospects. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1 This is a structural diagram of a picosecond laser processing system;

[0042] Figure 2 This is a schematic diagram of the picosecond laser scanning path in step (4) of embodiment 1 of the present invention;

[0043] Figure 3 The surface morphology (SEM) of the S,Se co-doped silicon-based near-infrared photosensitive material prepared after annealing in step (5) of Example 1 of the present invention is shown.

[0044] Figure 4 This is a secondary ion mass spectrum of the S,Se co-doped silicon-based near-infrared photosensitive material prepared after annealing in step (5) of Example 1 of the present invention;

[0045] Figure 5 The images show the Raman spectra of the S and Se co-doped samples before and after annealing in step (5) of Example 1 of this invention.

[0046] Figure 6 The image shows the broad spectrum absorption of the S-doped silicon-based material prepared in Comparative Example 1.

[0047] Figure 7 The image shows the broad spectrum absorption of the Se-doped silicon-based material prepared in Comparative Example 2.

[0048] Figure 8 The image shows the broad spectrum absorption of the S,Se co-doped silicon-based near-infrared photosensitive material prepared in Example 1. Detailed Implementation

[0049] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0050] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0051] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0052] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0053] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0054] This invention uses a SEM5000 field emission scanning electron microscope (Guoyi Quantum, China) to observe the surface morphology of S, Se co-doped silicon samples;

[0055] The longitudinal concentration distribution of S ions and Se atoms in the sample was analyzed in depth using time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0056] The inVia Qontor micro Raman spectrometer was used to measure the Raman spectra of S, Se co-doped silicon samples before and after annealing, in order to analyze the changes in the crystal phase of the S, Se co-doped silicon samples before and after annealing.

[0057] The reflectance R and transmittance T of three types of samples—S-doped silicon, Se-doped silicon, and S and Se co-doped silicon—were measured using a UV-VIS-NIR spectrophotometer. The absorbance was calculated using the formula A (absorbance) = 1 - R - T to reveal the synergistic effect enhancing the broadband absorption mechanism.

[0058] All raw materials used in this invention were purchased from the market.

[0059] The technical solution of the present invention will be further illustrated by the following embodiments.

[0060] Example 1

[0061] A method for preparing S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation includes the following steps:

[0062] (1) Preparation and cleaning of silicon wafers

[0063] An 8-inch low-resistivity silicon wafer with N-type (100) crystal orientation, 8-10 Ω·cm resistivity and a thickness of 500±25μm was selected and precisely cut into 10mm×10mm samples. After cutting, the wafers were immediately fixed on a silicon wafer holder and cleaned in sequence with acetone, anhydrous ethanol and deionized water, and then dried with high-purity nitrogen for later use.

[0064] (2) Thermal evaporation deposition of Se film

[0065] A 250 nm thick Se-doped thin film was prepared on a silicon substrate using a vacuum thermal deposition process. The deposition equipment used was a JSD-400 vacuum evaporation deposition machine manufactured by Anhui Jiashuo Vacuum Technology Co., Ltd. The specific operation was as follows:

[0066] First, 200 mg of 99.999% pure Se powder was loaded onto a tungsten evaporation boat. After the cleaned silicon wafer was fixed in the vacuum chamber, the vacuum level was reduced to 8.5 × 10⁻⁶ using a mechanical pump / molecular pump in combination. -4 Pa, then a current of 17 ± 0.5 A is applied to achieve Evaporation rate deposition, with film thickness gauge monitoring throughout the process. After completion, the machine is shut down, samples are taken, and the chamber is cleaned according to standard procedures.

[0067] (3) Setup of the picosecond laser processing system

[0068] A picosecond laser system for processing Se-coated silicon substrates, such as Figure 1 As shown, the system mainly consists of three parts: a laser source unit, an optical transmission unit, and a two-dimensional moving platform unit. The laser source system uses a modularly designed sealed laser head, capable of outputting a 1064nm picosecond laser (Berlin laser, Amber NX IR-10), with a maximum output power of 12W. The laser frequency range is adjustable between 50kHz and 2000kHz, and the minimum processing linewidth is between 15 and 20μm. The laser transmission unit includes a reflector, a beam expander, a dichroic mirror, a digital galvanometer scanning device (with fast response speed), and a 100mm telecentric lens. Through beam expansion, collimation, and galvanometer coordinated control, it ensures that the laser beam maintains perpendicular incidence and uniform energy density on the processing surface. The two-dimensional moving platform unit (micromachining platform) is driven by a stepper motor, combined with computer program control of the galvanometer scanning path (e.g., ...). Figure 2 As shown in the grid scanning mode, the laser beam first completes a single linear scan from point a to point b, thus constituting a complete work cycle. Then, the laser beam returns to point c and repeats the process. Simultaneously, the computer program can adjust parameters such as the laser scanning speed, the vertical laser scanning interval, and the area being processed.

[0069] (4) Fabrication of micro / nano-structured Se-doped silicon

[0070] Single-crystal silicon with a 250nm thick Se film deposited on its surface was placed into the cavity of a picosecond laser processing system for processing. During the picosecond laser processing, the laser single-pulse energy was selected as 4.5μJ, the pulse width as 8.7ps, the wavelength as 1064nm, the spot diameter as 20μm, the frequency as 2000kHz, and the average laser pulse energy density as 1.4kJ / m². 2 The scanning interval was 10 μm to ensure uniform exposure of the sample surface. The scanning speed was set to 100 mm / s, and the number of laser pulses received per unit area was N = 400. After scanning, black silicon with a micro-nano composite structure on the surface was obtained.

[0071] (5) High-energy ion implantation of S to achieve S, Se co-doping

[0072] Sulfur (S) ion implantation modification was performed on Se-doped black silicon samples that were sequentially cleaned with acetone, anhydrous ethanol, and deionized water: single-charged state (S) ions were selected. + The ion beam, after being screened by a magnetic analyzer, is subjected to a vacuum level better than 5 × 10⁻⁶. -4 In a target chamber environment with a target energy of 100 keV, the sample microstructure surface was vertically injected with an incident energy of 100 keV, and the injection dose was strictly controlled at 3 × 10⁻⁶ Pa. 16 ions / cm 2 (Dose uniformity deviation ≤ ±3%). Dose accumulation was monitored in real-time using a beam integrator during implantation. After ion implantation, a cleaning process was performed again, followed by drying with high-purity nitrogen. Finally, the sample was heated to 700℃ at a rate of 5℃ / min using a BTF-1200-II high-temperature tubular annealing furnace (Anhui Beiyike Co., Ltd., China), and annealed at 700℃ for 30 min to repair lattice damage. The nitrogen flow rate was 1.5 L / min, thus preparing S,Se co-doped silicon-based near-infrared photosensitive materials.

[0073] Comparative Example 1

[0074] The only difference from Example 1 is that the fabrication of micro / nano-structured Se-doped silicon is not performed. All other preparation steps and conditions are the same as in Example 1.

[0075] Comparative Example 2

[0076] The only difference from Example 1 is that high-energy ion implantation (S) is not performed. All other preparation steps and conditions are the same as in Example 1.

[0077] Figure 1 This is a structural diagram of a picosecond laser processing system;

[0078] Figure 2 This is a schematic diagram of the picosecond laser scanning path in step (4) of embodiment 1 of the present invention;

[0079] Figure 3The image shows the surface morphology (SEM) of the S, Se co-doped silicon-based near-infrared photosensitive material prepared in step (5) of Example 1 of this invention. As can be seen from the image, the periodic micro / nano composite structure constructed on the silicon surface by picosecond laser scanning (pulse width 8.7 ps, wavelength 1064 nm) exhibits a significant light-trapping enhancement effect (SEM characterization shows a periodic trench width of 10 μm ± 0.5 μm). This structure works synergistically through the following mechanisms: macroscopic trenches extend the optical path through geometric optics effects, and microscopic pores induce localized surface plasmon resonance (LSPR), which is particularly beneficial for enhancing near-infrared absorption; that is, the periodic micro / nano structure formed by picosecond laser scanning has a light-trapping enhancement effect.

[0080] Figure 4 The image shows the secondary ion mass spectrum of the S, Se co-doped silicon-based near-infrared photosensitive material prepared in step (5) of Example 1 of this invention. As can be seen from the image, the S, Se co-doped silicon-based near-infrared photosensitive material prepared by this invention has bipolar doping control through gradient band engineering: the picosecond laser-ion implantation synergistic doping process dops Se atoms and S ions respectively, and the S and Se concentration gradient distribution revealed by TOF-SIMS in-depth analysis forms a "bipolar doping" effect. The high Se concentration layer within 30 nm of the surface reduces the surface recombination rate, and the peak region of S ions appears within 620 nm of the subsurface to construct a built-in electric field. The concentration gradient forms a quasi-continuous conduction band structure, which promotes the directional transport of charge carriers.

[0081] Figure 5 The images show the Raman spectra of the S, Se co-doped samples before and after annealing in step (5) of Example 1 of this invention. As can be seen from the figures, the unannealed sample exhibits very low and almost flat intensity across the entire wavenumber range, indicating that the sample structure is relatively disordered or has many defects in the unannealed state, resulting in a weak Raman scattering signal. After annealing, the sample shows a lower intensity at approximately 510 cm⁻¹. -1 A distinct sharp peak appeared at 510 cm⁻¹, indicating that the sample structure underwent a significant change after annealing, possibly forming an ordered lattice structure or a specific chemical bonding state, thus generating a strong Raman scattering signal. In other words, by comparing the Raman spectra before and after annealing, it can be seen that annealing treatment has a significant impact on the structure of the S / Se co-doped sample. The annealed sample showed a sharp peak at 510 cm⁻¹. -1 The presence of significant Raman peaks nearby indicates that the annealing process promoted the rearrangement or crystallization of the sample's internal structure, enhancing the Raman activity of specific vibrational modes. This change is significant for understanding the mechanism of action of dopants and optimizing material properties. In other words, the lattice distortion caused by ion implantation has been repaired by the annealing treatment.

[0082] Figure 6The figure shows the broad-spectral absorption of the S-doped silicon-based material prepared in Comparative Example 1. As can be seen from the figure, the absorbance of untreated silicon drops sharply to near zero after 1000 nm. This indicates that untreated silicon has weak light absorption in this wavelength range. The S-doped silicon-based material maintains a relatively high absorbance after 1000 nm, indicating that S doping significantly enhances the light absorption of the silicon-based material across the entire wavelength range, especially in the near-infrared region.

[0083] Figure 7 The figure shows the broad-spectral absorption of the Se-doped silicon-based material prepared in Comparative Example 2. As can be seen from the figure, the absorbance of untreated silicon drops sharply to near zero after 1000 nm. This indicates that untreated silicon has weak light absorption in this wavelength range. The Se-doped silicon-based material exhibits significantly higher absorbance than untreated silicon across the entire wavelength range, especially after 1000 nm, where the absorbance remains at a high level. This demonstrates that Se doping significantly enhances the light absorption of silicon-based materials across the entire wavelength range, particularly in the near-infrared region.

[0084] Figure 8 The image shows the broad-spectral absorption spectrum of the S,Se co-doped silicon-based near-infrared photosensitive material prepared in Example 1. As can be seen from the image, the S,Se co-doped silicon-based material exhibits significantly higher absorbance across the entire wavelength range than untreated silicon, especially after 1000 nm, where the absorbance remains at a high level without a sharp decline. This indicates that S,Se co-doping significantly enhances the light absorption capability of the silicon-based material across the entire wavelength range, particularly in the near-infrared region. In other words, by comparing the absorption spectra of untreated silicon and S,Se co-doped silicon-based materials, it can be seen that S,Se co-doping has a significant impact on the optical properties of silicon-based materials. S,Se co-doping significantly improves the light absorption capability of the material across the entire wavelength range, especially in the near-infrared region, which may be of great significance for applications requiring high-efficiency light absorption, such as photovoltaics and photodetectors.

[0085] And through comparison Figure 6-8 It can be seen that the S,Se co-doped sample prepared in Example 1 of the present invention has an absorption rate of 82% at 1300 nm, which is significantly higher than the 51% and 64% of the S and Se single-doped silicon samples, respectively, proving that the mechanism lies in the formation of an intermediate band structure at the S-Se recombination center.

[0086] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation, characterized in that, Includes the following steps: A Se-doped thin film was deposited on the surface of a silicon substrate using a vacuum deposition process, and then a black silicon with a micro-nano composite structure was prepared by picosecond laser scanning. The black silicon with the micro-nano composite structure was modified by sulfur ion implantation and annealed to prepare the S, Se co-doped silicon-based near-infrared photosensitive material. The specific operation of the vacuum deposition process is as follows: After loading Se powder onto a tungsten evaporation boat and fixing the silicon substrate in a vacuum chamber, the process is carried out at a vacuum level of 8.5 × 10⁻⁶. -4 Under the condition of Pa, a current of 17±0.5A was applied and deposition was carried out at an evaporation rate of 3~5Å / s to obtain the Se-doped film; The conditions during the picosecond laser scanning process are as follows: The laser has a single-pulse energy of 4.5 ± 0.5 μJ, a pulse width of 8.7 ± 0.3 ps, a wavelength of 1064 nm, a spot diameter of 20 μm, a frequency of 2000 kHz, and an average laser pulse energy density of 1.4 ± 0.2 kJ / m². 2 The scanning interval is 10 μm, the scanning speed is 100 mm / s, and the number of laser pulses received per unit area is N=400; The conditions for the sulfur ion implantation modification are as follows: S + Ion beam in vacuum greater than 5×10 -4 Under the condition of Pa, the black silicon surface of the micro-nano composite structure was vertically injected with an incident energy of 100 keV, and the injection dose was 3 × 10⁻⁶ Pa. 16 ions / cm 2 ; The annealing conditions are as follows: annealing at 700 °C for 30 min.

2. The method for preparing S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation according to claim 1, characterized in that, The silicon substrate is an N-type (100) oriented silicon wafer with a resistivity of 8~10 Ω·cm.

3. The method for preparing S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation according to claim 1, characterized in that, The thickness of the Se-doped thin film is 250 nm.

4. The method for preparing S, Se co-doped silicon-based near-infrared photosensitive material based on picosecond laser-ion implantation according to claim 1, characterized in that, The atmosphere during the annealing process is nitrogen, and the flow rate of nitrogen is 1.5 L / min.

5. A near-infrared photosensitive material based on S and Se co-doped silicon, derived from picosecond laser-ion implantation, characterized in that... It is prepared by the preparation method according to any one of claims 1-4.

6. The application of S, Se co-doped silicon-based near-infrared photosensitive materials based on picosecond laser-ion implantation as described in claim 5 in the fabrication of photovoltaic devices and high-sensitivity infrared detectors.

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