CsCu3S2 semiconductor material, csCu3S2 / ga2O3 heterojunction and application thereof in photoelectric detection

Abstract

The application discloses a CsCu3S2 semiconductor material, a CsCu3S2 / Ga2O3 heterojunction and application of the CsCu3S2 / Ga2O3 heterojunction in photoelectric detection, and comprises the following steps: weighing cuprous sulfide, thiourea and cesium hydroxide monohydrate, and adding the cuprous sulfide, the thiourea and the cesium hydroxide monohydrate into a polytetrafluoroethylene inner container; adding ethylenediamine into the polytetrafluoroethylene inner container, sealing the polytetrafluoroethylene inner container, and loading the polytetrafluoroethylene inner container into a reaction kettle to pressurize, so as to form a closed self-pressure system; placing the reaction kettle in an oven to heat and keep warm, and naturally cooling to room temperature; sequentially performing cleaning and centrifugal treatment on the cooled reaction product; removing supernatant after centrifugation, vacuum drying the precipitate, and obtaining CsCu3S2 nanoparticle powder. The CsCu3S2 nanoparticle powder prepared by the application has high purity, good crystallinity, high light absorption activity and uniform morphology; meanwhile, the CsCu3S2 sheet is combined with Ga2O3 to form a heterojunction, and a silver paste electrode is combined to form a photoelectric detector with excellent self-power supply characteristics.

Description

Technical Field

[0001] This invention relates to a CsCu3S2 semiconductor material, a CsCu3S2 / Ga2O3 heterojunction, and their application in photoelectric detection, belonging to the technical field of new electronic materials and devices. Background Technology

[0002] Traditional photoelectric detection materials (such as silicon-based materials, InGaAs, HgCdTe, and vanadium oxide) have achieved large-scale application, but they have inherent technical bottlenecks: silicon-based materials have narrow band gaps, making it difficult to cover the entire spectrum from deep ultraviolet to near infrared detection; compound materials such as InGaAs and HgCdTe have problems such as stringent lattice matching requirements, complex preparation processes, and high costs; vanadium oxide materials face limitations such as slow response speed and narrow detection bands. These defects seriously restrict the development of photoelectric detection technology.

[0003] To overcome the performance bottlenecks of traditional materials, the development of novel semiconductor materials has become a research hotspot. Since its application in solar cells was reported in 2009, perovskite materials have achieved breakthroughs in solar cells, light-emitting diodes (LEDs), and photodetectors due to their excellent photoelectric properties, such as high light absorption coefficient, long carrier diffusion length, and tunable bandgap. However, the inherent poor stability of perovskite materials (susceptibility to decomposition due to humidity and temperature), the biotoxicity of lead-based materials, and the challenge of uniformity control during large-scale fabrication severely limit their practical applications. Therefore, developing low-cost, easily fabricated, high-performance, and environmentally friendly novel semiconductor materials has become an urgent need to promote the industrialization of optoelectronic devices.

[0004] Copper-based chalcogenides (CsCu3S2) have gradually become ideal candidate systems to replace perovskite materials due to their inherent non-toxicity, abundant raw material reserves, low preparation cost, and good environmental compatibility. Among the many CsCu3S2 compounds, the ternary chalcogenide CsCu3S2 has attracted research attention due to its unique crystal structure and electronic properties: Yue Jincheng et al. (Materials Today Physics, 2024, 46: 1011517) confirmed the excellent p-type thermoelectric properties of CsCu3S2 through the study of self-consistent phonon theory combined with linearized Wigner transport equations; Samira Idrissi et al. (Phase Transitions, 2024, 97: 813-825) showed through systematic analysis based on density functional theory that CsCu3S2 has a band gap of 2.236 eV and strong absorption characteristics in the ultraviolet region, and has potential application value in photovoltaic devices, photodetectors, optical filters, and other fields. Although theoretical studies have revealed the optoelectronic application potential of CsCu3S2, there are currently no reports on efficient preparation methods for CsCu3S2 materials or their practical applications in photoelectric detection. Its photoelectric response characteristics, heterostructure construction, and device applications remain in the exploratory stage. Therefore, developing controllable preparation processes for CsCu3S2 semiconductor materials and constructing high-performance photoelectric detection devices based on this material can not only fill relevant research gaps but also provide new material systems and technical solutions for broadband, self-powered photoelectric detection technologies, possessing significant academic value and application prospects. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a CsCu3S2 semiconductor material, a CsCu3S2 / Ga2O3 heterojunction, and its application in photoelectric detection. High-purity, well-crystallized, highly light-absorbing, and uniformly morphologically-rich CsCu3S2 nanoparticles are prepared. Simultaneously, a CsCu3S2 sheet is used as a light-absorbing layer and combined with Ga2O3 to form a heterojunction, which, combined with a silver paste electrode, forms a photodetector with excellent self-powered characteristics.

[0006] To achieve the above objectives, the present invention employs a method for preparing CsCu3S2 semiconductor materials, using cesium hydroxide monohydrate, cuprous sulfide, and thiourea as raw materials, and ethylenediamine as a solvent, to prepare CsCu3S2 nanoparticles through a one-step solvothermal reaction under high temperature and pressure. The method specifically includes the following steps:

[0007] (1) Weigh out cuprous sulfide, thiourea and cesium hydroxide monohydrate, and add them to the polytetrafluoroethylene liner;

[0008] (2) Add ethylenediamine to the polytetrafluoroethylene liner, seal it and put it into the reaction vessel to form a closed self-pressurized system;

[0009] (3) Place the reactor in an oven to heat and keep it warm, then let it cool naturally to room temperature;

[0010] (4) The cooled reaction products were washed and centrifuged in sequence;

[0011] (5) Remove the supernatant after centrifugation and vacuum dry the precipitate to obtain CsCu3S2 nanoparticle powder.

[0012] As an improvement, in step (1), the molar ratio of cuprous sulfide, thiourea and cesium hydroxide monohydrate is (1-5):1:(5-15).

[0013] As an improvement, in step (2), the amount of ethylenediamine added is 5-10 mL; in step (3), the oven heating temperature is 180-220℃ and the heat preservation time is 20-25 h.

[0014] As an improvement, in step (4), the cleaning is performed by alternating between deionized water and anhydrous ethanol, the centrifugation speed is 7000-9000 rpm, and the centrifugation time is 3-6 min; in step (5), the vacuum drying temperature is 50-70℃, and the drying time is 3-5 h.

[0015] In a second aspect, the present invention also provides a CsCu3S2 semiconductor material, which is prepared by the aforementioned preparation method.

[0016] A third aspect of the present invention also provides a CsCu3S2 / Ga2O3 heterojunction, wherein a heterojunction structure is formed by magnetron sputtering a Ga2O3 thin film onto the surface of the CsCu3S2 semiconductor material after it has been pressed into a sheet.

[0017] As an improvement, the pressure of the CsCu3S2 semiconductor material pressing sheet is 8-12 MPa, and the sheet thickness is 0.5-3 mm; the magnetron sputtering is carried out in an argon atmosphere, and the sputtering time is 20-40 min.

[0018] A fourth aspect of the present invention also provides the application of the CsCu3S2 / Ga2O3 heterojunction in semiconductor optoelectronic devices, wherein the semiconductor optoelectronic devices are photodetectors, solar cells, photoelectric memories, or photodiodes.

[0019] A fifth aspect of the present invention also provides a photodetector, the method for fabricating the photodetector comprising the following steps:

[0020] (1) The CsCu3S2 semiconductor material is used;

[0021] (2) Pressing CsCu3S2 semiconductor material into wafers;

[0022] (3) A Ga2O3 thin film is magnetron sputtered on the surface of the wafer to form a CsCu3S2 / Ga2O3 heterojunction;

[0023] (4) Ag paste is applied to the CsCu3S2 side and Ga2O3 side of the CsCu3S2 / Ga2O3 heterojunction respectively, and after vacuum drying, a photodetector with the structure Ag / CsCu3S2 / Ga2O3 / Ag is obtained.

[0024] As an improvement, in step (4), the vacuum drying temperature is 40-80℃ and the drying time is 20-40 min; the photodetector has self-powered characteristics under 0V bias and has photocurrent output in the 365 nm-1050 nm band.

[0025] Mechanism of the invention:

[0026] A one-step synthesis of pure-phase CsCu3S2 nanoparticles was achieved in a closed, self-pressurized reactor using cesium hydroxide monohydrate, cuprous sulfide, and thiourea as raw materials and ethylenediamine as solvent. Ethylenediamine functions as both a coordination solvent and a reaction medium, promoting efficient dissociation of the raw materials: cesium hydroxide monohydrate releases Cs... + Cuprous sulfide releases Cu + Thiourea slowly dissociates to form S 2- The three components form crystal nuclei through directional bonding according to stoichiometric ratios, with excess Cs... + By suppressing the formation of impurity phases and guiding the stable growth of the hexagonal crystal system, combined with the steric hindrance effect of ethylenediamine, CsCu3S2 nanoparticles with uniform morphology and high purity were finally obtained.

[0027] The construction of CsCu3S2 / Ga2O3 heterojunctions via CsCu3S2 powder pressing and Ga2O3 magnetron sputtering stems from the matching and tight interface construction of pn semiconductors. CsCu3S2 is a p-type narrow bandgap semiconductor (bandgap 1.89 eV), while Ga2O3 is an n-type wide bandgap semiconductor (bandgap ~4.8 eV). Upon contact, due to the Fermi level difference, a built-in electric field is formed at the interface pointing from n-Ga2O3 to p-CsCu3S2. Magnetron sputtering technology achieves atomic-level tight contact, eliminating interfacial voids and laying the foundation for efficient carrier transport.

[0028] The p-CsCu3S2 / n-Ga2O3 heterojunction interface of this invention forms a stable depletion layer and a built-in electric field: Under illumination, CsCu3S2 absorbs photon energy to excite electron-hole pairs. Under the directional driving effect of the built-in electric field, electrons and holes are rapidly separated and directionally transported to the n-type Ga2O3 side and the p-type CsCu3S2 side, respectively, and are finally efficiently collected by the corresponding side electrodes, forming a stable photogenerated current and photogenerated voltage. At the same time, the rectifying barrier formed by the heterojunction can significantly suppress the disordered migration of charge carriers in the dark state, greatly reduce the dark current density, and effectively improve the detection signal-to-noise ratio of the device. Relying on the charge carrier separation driving force provided by the built-in electric field, this heterojunction can achieve efficient photodetection without external bias voltage and has excellent zero-bias self-driven operating characteristics.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] (1) The preparation process of this invention is simple and efficient. The solvothermal one-step reaction does not require complex pretreatment or purification, making it suitable for large-scale production. The raw materials are inexpensive and readily available and do not contain toxic elements such as lead and cadmium, and have excellent environmental compatibility. By precisely controlling the molar ratio of raw materials and process parameters, pure-phase, uniform-morphology, and highly crystalline CsCu3S2 nanoparticles can be stably obtained, solving the problem of multiphase mixing in the synthesis of traditional copper chalcogenides.

[0031] (2) The CsCu3S2 / Ga2O3 heterojunction has both excellent interface quality and performance synergy. The tight interface constructed by magnetron sputtering greatly reduces the carrier transport resistance, and the strong built-in electric field formed by pn-type semiconductor matching significantly improves the carrier separation efficiency. At the same time, it combines the narrow bandgap and wide wavelength absorption characteristics of CsCu3S2 with the high stability of Ga2O3, which not only expands the photoresponse range, but also enhances the thermal and chemical stability of the material.

[0032] (3) The photodetector exhibits the core advantages of self-powered, wide-band, and high-performance: it can work stably under 0V bias without external power supply, making it suitable for low-power and portable sensing scenarios; the optical response band covers the 365nm-1050nm ultraviolet-visible-near-infrared region, solving the defect of narrow detection band of traditional materials; the silver paste electrode has good contact with the heterojunction, high carrier collection efficiency, stable photocurrent signal, and excellent detection sensitivity, and the preparation process is mature and compatible with existing semiconductor processing technology, showing outstanding industrialization potential.

[0033] (4) This invention is the first to use CsCu3S2 material in the construction of a self-powered photodetector, filling the application gap of this material in the field of photodetection and expanding the application boundaries of ternary copper chalcogenide compounds. The heterojunction and device can be widely adapted to semiconductor optoelectronic devices such as photodetectors, solar cells, and photoelectric memories, and has irreplaceable application value in key fields such as consumer electronics, autonomous driving, and industrial monitoring, with broad market prospects. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of Embodiment 3 of the present invention;

[0035] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the CsCu3S2 semiconductor material prepared in Example 2 of this invention.

[0036] Figure 3 This is a scanning electron microscope (SEM) image of the CsCu3S2 semiconductor material prepared in Example 2 of the present invention, wherein... Figure 3 (a) is a SEM image at 2200x magnification, showing the overall morphological characteristics of the material; Figure 3 (b) is a detailed morphological characterization of a single particle under a magnification of 13,000x;

[0037] Figure 4 The ultraviolet-visible-near-infrared diffuse reflectance conversion absorption spectrum of the CsCu3S2 semiconductor material prepared in Example 2 of this invention;

[0038] Figure 5 The image shows the Raman spectrum of the CsCu3S2 semiconductor material prepared in Example 2 of this invention.

[0039] Figure 6 The energy dispersive X-ray spectrum (EDS) of the CsCu3S2 semiconductor material prepared in Example 2 of this invention is shown below.

[0040] Figure 7 The current-voltage characteristic curves of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of Example 3 of the present invention under illumination of light at different wavelengths from 365 nm to 1050 nm are shown.

[0041] Figure 8 The photocurrent-time (It) characteristic curves of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of Example 3 of the present invention under illumination with light of different wavelengths from 365 nm to 1050 nm;

[0042] Figure 9The current-voltage characteristic curves of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector under different intensities of 625 nm light irradiation in Example 3 of this invention are shown.

[0043] Figure 10 The above are the It characteristic curves of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of Example 3 of the present invention under different intensities of 625 nm light irradiation.

[0044] Figure 11 This is the response-recovery time curve of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector in Example 3 of the present invention under 625 nm light irradiation;

[0045] Figure 12 The thermogravimetric (TG) curve of the CsCu3S2 semiconductor material prepared in Example 2 of this invention is shown. Detailed Implementation

[0046] The following embodiments are further illustrations of the present invention and serve as explanations of the technical content of the present invention. However, the essence of the present invention is not limited to the embodiments described below. Those skilled in the art can and should know that any simple changes or substitutions based on the spirit of the present invention should fall within the protection scope claimed by the present invention.

[0047] Example 1

[0048] In this embodiment, CsCu3S2 semiconductor material is prepared according to the following steps:

[0049] Step 1: Weigh out 6.25 mmol of cuprous sulfide, 1.25 mmol of thiourea (molar ratio of cuprous sulfide to thiourea is 5:1), and 12.5 mmol of cesium hydroxide monohydrate in sequence, and pour them into a polytetrafluoroethylene (PTFE) inner liner; then add 6 mL of ethylenediamine to the PTFE inner liner, tighten the inner liner lid and place it into a solvothermal reactor, tighten the reactor body to form a closed self-pressurized system; place the reactor in an oven and keep it at 200°C for 24 hours, then allow it to cool naturally to room temperature;

[0050] Step 2: Transfer the reaction product in the cooled reactor to a centrifuge tube using a pipette. Wash the tube five times alternately with deionized water and anhydrous ethanol (washing sequence: deionized water → deionized water → anhydrous ethanol → deionized water → anhydrous ethanol). Centrifuge after each wash and discard the supernatant. The centrifugation speed is 8000 rpm and the centrifugation time is 5 min. Then remove the remaining supernatant from the centrifuge tube and place the obtained precipitate in a vacuum drying oven and dry it at 60°C for 4 hours to obtain CsCu3S2 semiconductor material.

[0051] In this embodiment, the product yield was calculated by the ratio of the final synthesized powder mass to the theoretical yield of the raw materials. In this embodiment, 1.115 g of CsCu3S2 powder was actually obtained, and based on the molar mass of copper in the compound, the yield was 69.1%.

[0052] Example 2

[0053] In this embodiment, CsCu3S2 semiconductor material is prepared according to the following steps:

[0054] Step 1: Based on Example 1, adjust the amount of cuprous sulfide to 3.75 mmol, maintaining the molar ratio of cuprous sulfide to thiourea at 3:1; weigh 3.75 mmol of cuprous sulfide, 1.25 mmol of thiourea, and 12.5 mmol of cesium hydroxide monohydrate in sequence and pour them into a polytetrafluoroethylene (PTFE) inner liner; then add 6 mL of ethylenediamine to the PTFE inner liner, tighten the inner liner lid and place it in a solvothermal reactor, tighten the reactor body to form a closed self-pressurized system; place the reactor in an oven and keep it at 200°C for 24 hours, then allow it to cool naturally to room temperature;

[0055] Step 2, same as in Example 1.

[0056] In this embodiment, 0.801 g of CsCu3S2 powder was actually obtained. Based on the molar mass of copper in the compound, the yield was 82.5%.

[0057] Example 3

[0058] In this embodiment, an Ag / CsCu3S2 / Ga2O3 / Ag photodetector based on a CsCu3S2 / Ga2O3 heterojunction is prepared according to the following steps:

[0059] Step 1: Compress CsCu3S2 powder into tablets

[0060] Using an FW-4A tablet press, 300 mg of CsCu3S2 powder prepared in Example 2 was poured into a tablet mold and assembled. The mold was placed at the pressure center of the tablet press, the pressure relief valve was tightened, and the hand crank was turned downwards until the pressure gauge indicated a pressure of 10 MPa. After holding the pressure for 10 minutes, the oil release valve was loosened counterclockwise to release the pressure. The mold was removed from the tablet press to obtain CsCu3S2 discs with a diameter of 1 cm and a thickness of 1 mm.

[0061] Step 2: Sputtering Ga2O3 thin film

[0062] The CsCu3S2 wafer was placed in a magnetron sputtering instrument and sputtered with a Ga2O3 target at a power of 130W under an argon atmosphere for 30 minutes to form a Ga2O3 thin film on the surface of the CsCu3S2 wafer, thus obtaining a CsCu3S2 / Ga2O3 heterojunction.

[0063] Step 3: Prepare Ag electrode

[0064] Ag paste was spot-coated on the CsCu3S2 side and Ga2O3 side of the CsCu3S2 / Ga2O3 heterojunction, and then dried in a vacuum drying oven at 60℃ for 30 min to obtain a photodetector with the structure Ag / CsCu3S2 / Ga2O3 / Ag.

[0065] Figure 1 This is a schematic diagram of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of the present invention, wherein CsCu3S2 serves as the light absorption layer and forms a heterojunction with the Ga2O3 thin film, and silver paste serves as the bottom electrode and top electrode, respectively.

[0066] Figure 2 The image shows the XRD pattern of the CsCu3S2 semiconductor material prepared in Example 2 of this invention. As can be seen from the image, the diffraction peaks at 13.9°, 23.4°, 28.1°, 35.7°, 37.9°, 46.9°, 47.8°, and 53.1° correspond one-to-one with the characteristic diffraction peaks of the hexagonal CsCu3S2 standard card (PDF#97-002-3326). No impurity diffraction peaks were observed, indicating that pure-phase hexagonal CsCu3S2 powder was successfully prepared.

[0067] Figure 3 The image shows the SEM image of the CsCu3S2 semiconductor material prepared in Example 2 of this invention. It can be observed that the material has a relatively uniform particle morphology with an average size of about 5 μm.

[0068] Figure 4 The ultraviolet-visible-near-infrared diffuse reflectance conversion absorption spectrum of the CsCu3S2 semiconductor material prepared in Example 2 of this invention was converted using the Kubelka-Munk formula, and then tangent fitting was performed on the absorption cutoff edge to obtain a band gap of 1.89 eV for the CsCu3S2 material.

[0069] Figure 5 The Raman spectrum of the CsCu3S2 semiconductor material prepared in Example 2 of this invention (test conditions: 633nm wavelength laser as light source, room temperature environment) shows that at 346cm... -1 1130cm -1 1517cm -1 The presence of a characteristic peak of CsCu3S2 at the point verifies the structural integrity of the material.

[0070] Figure 6The EDS spectrum of the CsCu3S2 semiconductor material prepared in Example 2 of this invention shows that the average atomic percentages of Cs, Cu, and S are 14.2%, 58.4%, and 27.4%, respectively, approximately 1:3:2, consistent with the stoichiometric ratio of CsCu3S2. These test results confirm that pure-phase CsCu3S2 powder was successfully synthesized via a solvothermal method.

[0071] Figure 7 This figure shows the current-voltage characteristic curves of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of the present invention under illumination of different wavelengths of light from 365nm to 1050nm, within a voltage range of ±1V. As can be seen from the figure, under the same bias voltage, the photocurrent corresponding to each wavelength of light is significantly higher than the dark current, proving that the detector has a significant photoelectric response capability to light in the 365nm-1050nm band.

[0072] Figure 8 The image shows the It characteristic curves of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of this invention under illumination of different wavelengths from 365nm to 1050nm and a bias voltage of 0V. The device exhibits a significant optical switching response under excitation light of all wavelengths, with the best response performance under 625nm excitation light. The effective response at 0V bias indicates that the device possesses self-powered characteristics, with a dark current density of 4.15 × 10⁻⁶. -5 A・cm -2 .

[0073] Figure 9 The figures show the current-voltage characteristics of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of this invention under different intensities of 625nm light irradiation within a voltage range of ±1V.

[0074] Figure 10 The figure shows the It characteristic curves of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of this invention under different intensities of 625nm light irradiation and 0V bias voltage. As can be clearly seen from the figure, as the light intensity increases from 17mW / cm², the performance of the photodetector increases. 2 Increased to 131.7 mW / cm 2 The photocurrent of the device gradually increases with increasing light intensity, exhibiting good light intensity dependence.

[0075] Figure 11 The diagram shows the response time of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector of this invention under 625nm light irradiation. The test results show that the rise time of the device is 4.19s and the fall time is 3.97s.

[0076] Figure 12This is the thermogravimetric curve (TGA) of the CsCu3S2 semiconductor material prepared in Example 2 of this invention. One of the significant advantages of the Ag / CsCu3S2 / Ga2O3 / Ag photodetector is its excellent durability, which is crucial for practical applications. The thermal stability of the material was assessed by thermogravimetric analysis: a slight decrease in mass occurred in the 100℃-300℃ range, presumably due to the evaporation of residual solvent; a slow decrease in mass occurred in the 300℃-800℃ range, possibly due to gradual decomposition or oxidation of the material; the differential thermogravimetric curve showed a sharp peak in the 100℃-300℃ range, corresponding to rapid weight loss in this stage, indicating a fast reaction rate and concentrated process; after 300℃, the curve tended to flatten, consistent with the slow decrease in the TGA curve. At 800℃, the material still retained more than 95% of its mass, demonstrating its good thermal stability.

[0077] This invention provides a method for preparing CsCu3S2 semiconductor material and an application example of CsCu3S2 / Ga2O3 heterojunction in photodetector. Using cesium hydroxide monohydrate, cuprous sulfide, and thiourea as raw materials and ethylenediamine as solvent, pure-phase hexagonal CsCu3S2 particles are prepared through a one-step solvothermal reaction under high temperature and pressure. By adjusting the molar ratio of cuprous sulfide to thiourea (as in Example 2), making the raw material ratio close to the stoichiometric coefficient of the chemical equation, the yield of CsCu3S2 can be effectively improved. The CsCu3S2 particles prepared in Example 2 have a relatively uniform morphology, an average size of approximately 5 μm, and a band gap of 1.89 eV, making them an ideal material for preparing photodetectors. After pressing CsCu3S2 powder into sheets, it is composited with Ga2O3 semiconductor to construct a CsCu3S2 / Ga2O3 heterojunction photodetector. This device exhibits excellent self-powered photodetector performance under 0V bias, with a dark current density as low as 4.15 × 10⁻⁶. -5 A・cm -2 It also exhibits a significant photoresponse across a wide spectral range of 365nm-1050nm.

[0078] In summary, this invention not only provides an efficient and feasible synthesis route for CsCu3S2 semiconductor materials, but also demonstrates its practical application value in the field of photoelectric detection through the construction of heterojunction devices. It provides important technical reference and experimental basis for the controllable preparation of novel semiconductor materials and their functional applications in optoelectronic devices.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing CsCu3S2 semiconductor material, characterized in that, CsCu3S2 nanoparticles were prepared via a one-step solvothermal reaction under high temperature and pressure using cesium hydroxide monohydrate, cuprous sulfide, and thiourea as raw materials and ethylenediamine as solvent. Ethylenediamine functions as both a coordination solvent and a reaction medium, promoting efficient dissociation of the raw materials and releasing Cs from the cesium hydroxide monohydrate. + Cuprous sulfide releases Cu + Thiourea slowly dissociates to form S 2- ; Specifically, the following steps are included: (1) Weigh out cuprous sulfide, thiourea and cesium hydroxide monohydrate, and add them to the polytetrafluoroethylene liner; (2) Add ethylenediamine to the polytetrafluoroethylene liner, seal it and put it into the reaction vessel to form a closed self-pressurized system; (3) Place the reactor in an oven to heat and keep it warm, then let it cool naturally to room temperature; (4) The cooled reaction products were washed and centrifuged in sequence; (5) Remove the supernatant after centrifugation and dry the precipitate under vacuum to obtain pure hexagonal CsCu3S2 nanoparticle powder.

2. The method for preparing CsCu3S2 semiconductor material as described in claim 1, characterized in that, In step (1), the molar ratio of cuprous sulfide, thiourea and cesium hydroxide monohydrate is (1-5):1:(5-15).

3. The method for preparing CsCu3S2 semiconductor material as described in claim 1, characterized in that, In step (2), the amount of ethylenediamine added is 5-10 mL; in step (3), the oven heating temperature is 180-220℃ and the heat preservation time is 20-25h.

4. The method for preparing CsCu3S2 semiconductor material as described in claim 1, characterized in that, In step (4), the cleaning is performed by alternating between deionized water and anhydrous ethanol, the centrifugation speed is 7000-9000 rpm, and the centrifugation time is 3-6 min; in step (5), the vacuum drying temperature is 50-70℃, and the drying time is 3-5 h.

5. CsCu3S2 semiconductor material, characterized in that, It is prepared by the preparation method according to any one of claims 1-4.

6. A CsCu3S2 / Ga2O3 heterojunction, characterized in that, The CsCu3S2 semiconductor material described in claim 5 is pressed into a wafer, and a Ga2O3 thin film is magnetron sputtered on its surface to form a heterojunction structure.

7. The CsCu3S2 / Ga2O3 heterojunction as described in claim 6, characterized in that, The pressure of the CsCu3S2 semiconductor material pressing sheet is 8-12 MPa, and the sheet thickness is 0.5-3 mm; the magnetron sputtering is carried out in an argon atmosphere, and the sputtering time is 20-40 min.

8. The application of the CsCu3S2 / Ga2O3 heterojunction as described in any one of claims 6-7 in semiconductor optoelectronic devices, characterized in that, The semiconductor optoelectronic device is a photodetector, a solar cell, a photoelectric memory, or a photodiode.

9. A photodetector, characterized in that, The method for fabricating the photodetector includes the following steps: (1) The CsCu3S2 semiconductor material described in claim 5 is used; (2) Pressing CsCu3S2 semiconductor material into wafers; (3) A Ga2O3 thin film is magnetron sputtered on the surface of the wafer to form a CsCu3S2 / Ga2O3 heterojunction; (4) Ag paste is applied to the CsCu3S2 side and Ga2O3 side of the CsCu3S2 / Ga2O3 heterojunction respectively, and after vacuum drying, a photodetector with the structure Ag / CsCu3S2 / Ga2O3 / Ag is obtained.

10. The photodetector as claimed in claim 9, characterized in that, In step (4), the vacuum drying temperature is 40-80℃ and the drying time is 20-40 min; the photodetector has self-powered characteristics under 0V bias and has photocurrent output in the 365 nm-1050 nm band.

Images