High-performance photoelectric detector based on ZnIn2S4 / Bi heterojunction

Abstract

The invention discloses a ZnIn2S4 / Bi heterojunction-based high-performance photoelectric detector, which is characterized in that FTO (Fluorine-doped Tin Oxide) conductive glass is sequentially put into a beaker containing acetone, absolute ethyl alcohol and deionized water, and is put into an ultrasonic cleaner to be cleaned for 20 minutes and 2-3 times respectively, so that organic pollutants, inorganic pollutants and the like on the surface of the FTO conductive glass can be removed; the prepared detector has good photoresponse characteristics and adjustable characteristics, the photocurrent density and the photoresponse rate can reach 42.08 microamperes / cm < 2 > and 295.31 microamperes / W respectively, the period rising time and the period falling time are 0.20 s and 0.33 s respectively, a ZnIn2S4 photoelectric device has high response speed, good period and time stability and the like, and the photoelectric device can be applied to the field of photoelectric devices. In addition, the simple substance ZnIn2S4 is limited in light absorption capacity, high in carrier recombination rate and the like, a built-in electric field formed by the simple substance ZnIn2S4 and the photoelectric detector for preparing the ZnIn2S4 and Bi vertical structure heterojunction can promote separation of photon-generated carriers, and the light response characteristic of the photoelectric detector is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric detectors, and in particular to a ZnIn 2 S 4 / Bi heterojunction high-performance photodetector. Background Art

[0002] With the rapid development of the semiconductor industry, the demand for electronics and optoelectronics is increasing. Due to their superior optical and electrical properties, two-dimensional materials have shown excellent performance and good application prospects in various photodetectors, including photoelectrochemical (PEC) photodetectors. Photodetectors can convert collected optical signals into electrical signals for data processing and analysis, and are widely used in daily life, including environmental monitoring, medical imaging, optical communications, and security inspections.

[0003] Graphene-based photodetectors have a large specific surface area, good in-plane thermal conductivity, and ultra-high carrier mobility, which promotes its application in ultrafast response high-frequency photodetectors. Black phosphorus-based photodetectors have unique properties. Black phosphorus in the form of bulk material has strong anisotropy, showing an armchair-type longitudinally staggered hexagonal lattice structure. The bandgap width of black phosphorus depends on the number of layers of the material, and its spectral absorption range also covers the visible light to near-infrared region. Few-layer black phosphorus has a higher carrier mobility, and black phosphorus also has a higher current switching ratio. Although graphene has a high light absorption coefficient, it can only absorb 2.3% of visible light and infrared incident light due to the thickness limitation of a single-layer graphene. In addition, since the bandgap width of graphene is zero, the lifetime of photogenerated carriers in the detector is short, which is not conducive to the generation of effective photocurrent. The instability of black phosphorus in ambient air greatly hinders the application and application scenarios of black phosphorus photodetectors. Summary of the invention

[0004] In order to solve the above problems, the present invention has developed a ZnIn 2 S 4 High-performance photodetectors based on ZnIn / Bi heterojunctions 2 S 4 Photoelectric devices have fast response speed and good cycle and time stability. 2 S 4 For photodetectors with vertical heterojunction structures with Bi, the built-in electric field formed by the two can promote the separation of photogenerated carriers and further improve the photoresponse characteristics of the photodetector.

[0005] In order to solve the above technical problems, the present invention provides a ZnIn 2 S 4A high-performance photodetector for a / Bi heterojunction includes the following steps:

[0006] S1. Place the FTO conductive glass in a beaker containing acetone, anhydrous ethanol and deionized water in turn, and put it into an ultrasonic cleaner for cleaning. Clean for 20 minutes each, 2 to 3 times, to remove organic and inorganic pollutants on the surface of the FTO conductive glass. After cleaning, use a nitrogen air gun to blow dry the residual water on the surface of the FTO conductive glass in one direction to obtain an FTO conductive glass without any pollutants on the surface to ensure the purity of the coating.

[0007] S2. Fix the cleaned FTO conductive glass and place it in the vacuum deposition chamber of the pulse laser deposition system. After closing the pulse laser deposition system, turn on the vacuum mechanical pump of the pulse laser deposition system to pump the vacuum degree in the deposition chamber to below 10Pa. Then turn on the solenoid valve and molecular pump of the pulse laser deposition system to further evacuate the vacuum degree in the deposition chamber to 10 -4 Pa level;

[0008] S3. After reaching the vacuum level described in S2, open the gas cylinder of the pulse laser deposition system to introduce argon gas into the deposition chamber, and use the principle of glow discharge to perform plasma cleaning on the conductive glass to further remove pollutants and ensure the cleanliness of the deposition substrate. After cleaning for 10 minutes, close the gas cylinder of the pulse laser deposition system and wait for the molecular pump of the pulse laser deposition system to continue to pump the vacuum level in the deposition chamber to 10 -5 Pa level, finally reaching the ideal deposition conditions and obtaining the sample;

[0009] S4. Mix the sample with ZnIn 2 S 4 The distance between the targets was set to 5 cm, and the sample and ZnIn were turned on in the pulsed laser deposition system. 2 S 4 The target material is turned on and off, so that the film is formed evenly and continuously during the deposition process;

[0010] S5, preheating the solid laser of the pulse laser deposition system to perform a pulse laser deposition experiment;

[0011] S6. After deposition, ZnIn is converted in situ by the external knob of the pulsed laser deposition system. 2 S 4 The target material ensures a high vacuum coating environment to avoid the introduction of impurities, and then continues to vertically deposit ZnIn on the Bi basis 2 S 4 After the deposition process is completed, the pulsed laser deposition system is turned off, and the sample is taken out after cooling to obtain a ZnIn2S4 / Bi heterojunction.

[0012] Preferably, the prepared ZnIn2 S 4 The / Bi heterojunction as a whole is used as the anode working electrode, and the counter electrode platinum sheet, saturated calomel electrode and the configured hydroxide solution are used as electrolytes to form a photoelectrochemical photodetector. When the light source irradiates the working system, the photoelectric signal is captured by the photoelectrochemical workstation.

[0013] Preferably, the solid laser of the pulse laser deposition system has an emission wavelength of 532 nm, an output voltage of 760 V, a pulse frequency of 4 Hz, and a laser single pulse energy of about 480 mJ.

[0014] Preferably, the laser of the solid laser of the pulsed laser deposition system is focused by a lens at an incident angle of 45° and irradiated onto the surface of the target material for 30 minutes.

[0015] Preferably, the photocurrent density of the photoelectrochemical photodetector reaches 42.08 μA / cm 2 ,The photoresponsivity of the photoelectrochemical photodetector reaches 295.31μA / W.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The detector prepared by the present invention has good photoresponse characteristics and adjustable characteristics, and the photocurrent density and photoresponse rate can reach 42.08μA / cm 2 and 295.31μA / W, the cycle rise and fall times are approximately 0.20s and 0.33s respectively, ZnIn 2 S 4 Photoelectric devices have a fast response speed and good cycle and time stability. In addition, the light absorption capacity of single-substance ZnIn2S4 is limited and the carrier recombination rate is fast. 2 S 4 For photodetectors with vertical heterojunction structures with Bi, the built-in electric field formed by the two can promote the separation of photogenerated carriers and further improve the photoresponse characteristics of the photodetector. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 To prepare two-dimensional ZnIn by pulsed laser deposition 2 S 4 Schematic diagram of / Bi film;

[0019] Figure 2 (a) is ZnIn 2 S 4 Atomic force microscopy (AFM) images of the film surface morphology: (b) is a scanning electron microscopy (SEM) image showing the surface morphology of the ZnIn2S4 film; (c), (d), and (g) are ZnIn2 S 4 X-ray diffraction (XRD) spectra of Zn, In, and S elements in the film; (e) is the AFM image of the ZIS / Bi film; (f) is the SEM image of the surface morphology of the ZIS / Bi film; (h) is the XRD image corresponding to ZIS / Bi;

[0020] Figure 3 (a) is ZnIn 2 S 4 VB XPS test of (a) VBXPS test of Bi;

[0021] Figure 4 (a) is a two-dimensional ZnIn 2 S 4 Linear sweep voltammetric test curve of photoelectrochemical photodetector; (b) ZnIn 2 S 4 Photoresponse behavior of the photodetector at different concentrations and incident light powers; (c) is the photoresponse behavior of the ZIS photodetector at different bias voltages and incident light powers: (d) is Iph at different wavelengths and power intensities; (e) is Rph at different wavelengths and power intensities; (f) is D* at different wavelengths and power intensities;

[0022] Figure 5 (a) is the photoresponse behavior of the ZIS photodetector at different wavelengths and incident light powers; (b) is a bar graph of the photoresponse behavior; (c) is the photoresponse time test of the ZIS photodetector in 1.0 mol / L KOH; (d) is the photoresponse curve of the ZIS photodetector at 380 nm, 450 nm, 550 nm and 650 nm;

[0023] Figure 6 (a) is a comparison of the linear sweep voltammetry curves of ZIS / Bi and ZIS photochemical photodetectors under illumination; (b) is a comparison of the linear sweep voltammetry curves of two-dimensional ZnIn 2 S 4 (a) Linear sweep voltammetric test curve of ZIS / Bi photoelectrochemical photodetector; (c) Photoresponse behavior of ZIS / Bi photodetector under different bias voltages and incident light powers; (d) Comparison of photoresponse curves of ZIS / Bi and ZIS at 0.6V; (e) Comparison of photocurrents of ZIS / Bi and ZIS under different bias voltages; (f) Comparison of photocurrent responses of ZIS / Bi and ZIS under different bias voltages;

[0024] Figure 7 The light response time test of ZIS / Bi photodetector in 1.0mol / LKOH;

[0025] Figure 8The ZIS / Bi band structure and contact diagram. DETAILED DESCRIPTION

[0026] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0027] The present invention provides a technical solution: a ZnIn 2 S 4 A high-performance photodetector for a / Bi heterojunction includes the following steps:

[0028] S1. Place the FTO conductive glass in a beaker containing acetone, anhydrous ethanol and deionized water in turn, and put it into an ultrasonic cleaner for cleaning. Clean for 20 minutes each, 2 to 3 times, to remove organic and inorganic pollutants on the surface of the FTO conductive glass. After cleaning, use a nitrogen air gun to blow dry the residual water on the surface of the FTO conductive glass in one direction to obtain an FTO conductive glass without any pollutants on the surface to ensure the purity of the coating.

[0029] S2. Fix the cleaned FTO conductive glass and place it in the vacuum deposition chamber of the pulse laser deposition system (PLD). After closing the pulse laser deposition system, turn on the vacuum mechanical pump of the pulse laser deposition system to pump the vacuum degree in the deposition chamber to below 10Pa. Then, turn on the solenoid valve and molecular pump of the pulse laser deposition system to further evacuate the vacuum degree in the deposition chamber to 10 -4 Pa level;

[0030] S3. After reaching the vacuum level described in S2, open the gas cylinder of the pulse laser deposition system to introduce argon gas into the deposition chamber, and use the principle of glow discharge to perform plasma cleaning on the conductive glass to further remove pollutants and ensure the cleanliness of the deposition substrate. After cleaning for 10 minutes, close the gas cylinder of the pulse laser deposition system and wait for the molecular pump of the pulse laser deposition system to continue to pump the vacuum level in the deposition chamber to 10 -5 Pa level, finally reaching the ideal deposition conditions and obtaining the sample;

[0031] S4. Mix the sample with ZnIn 2 S 4 The distance between the targets was set to 5 cm, and the sample and ZnIn were turned on in the pulsed laser deposition system. 2 S 4 The target material is turned on and off, so that the film is formed evenly and continuously during the deposition process;

[0032] S5. Preheat the solid laser of the pulse laser deposition system. The emission wavelength of the solid laser of the pulse laser deposition system is 532nm, the output voltage is 760V, the pulse frequency is 4Hz, and the laser single pulse energy is about 480mJ. The laser of the solid laser of the pulse laser deposition system is focused by a lens at an incident angle of 45° and irradiated onto the surface of the target material. The time is set to 30 minutes to conduct a pulse laser deposition experiment.

[0033] S6. After deposition, ZnIn is converted in situ by the external knob of the pulsed laser deposition system. 2 S 4 The target material ensures a high vacuum coating environment to avoid the introduction of impurities, and then continues to vertically deposit ZnIn on the Bi basis 2 S 4 After the deposition process is completed, the pulse laser deposition system is turned off, and the sample is taken out after cooling to obtain ZnIn 2 S 4 / Bi heterojunction.

[0034] In this example, the prepared ZnIn 2 S 4 / Bi heterojunction as anode working electrode, platinum electrode, saturated calomel electrode and prepared hydroxide solution as electrolyte to form a photoelectrochemical photodetector. When the light source irradiates the working system, the photoelectric signal is captured by the photoelectrochemical workstation. The photocurrent density of the photoelectrochemical photodetector reaches 42.08μA / cm 2 ,The photoresponsivity of the photoelectrochemical photodetector reaches 295.31μA / W.

[0035] This embodiment is prepared by pulsed laser deposition method. Compared with other material preparation methods, the pulsed laser deposition system has the following advantages:

[0036] (1) Lower growth temperature, i.e., lower substrate heating temperature, which enables pulsed laser deposition to deposit materials on many substrates that cannot withstand high temperatures. For example, many flexible substrates have poor high temperature tolerance, which means that many processes must be deposited on other substrates before transfer, while pulsed laser deposition technology can be directly deposited on these substrates;

[0037] (2) The grown materials have good uniformity and can grow large-area nanomaterials, reaching the centimeter scale, which facilitates the construction of large-area optoelectronic device arrays;

[0038] (3) In addition, PLD can prepare multilayer structures with fewer impurities and can more easily construct heterojunctions. At the same time, thanks to the ultra-high vacuum provided by mechanical pumps and molecular pumps, the materials deposited by pulsed lasers can maintain high purity.

[0039] The ZnIn prepared in this example 2 S 4 The Bi / Si thin film heterojunction photodetector has excellent photoelectric performance and obvious switching behavior. It generates a large amount of photocurrent under appropriate bias voltage, with a photocurrent density of 42.08μA / cm 2 , the response rate is high, which is 295.31μA / W, and the response speed is also fast (the rise / fall time is 0.20s and 0.33s). Based on these test results, this photodetector is superior to other photodetectors of the same type, and its performance is also better than that of ZnIn 2 S 4 Photoelectric detector, these excellent properties indicate that the device has better ability to collect optical signals and convert them into electrical signals for data processing and analysis, and has better application prospects.

[0040] The ZnIn prepared in this example 2 S 4 / Bi heterojunction photodetectors belong to photoelectrochemical photodetectors, which are a new type of self-powered photodetectors. Compared with other types of self-powered photodetectors, their manufacturing process is simpler, avoiding complex photolithography processes, and have the advantages of self-powered, high responsiveness, ability to work in acid / alkaline solutions, and environmental friendliness. At the same time, the photocurrent is larger than that of most self-powered photodetectors, and the output current can reach the microampere level, while the output photocurrent of ordinary self-powered photoelectrochemical photodetectors is generally in the nanoampere level;

[0041] Based on ZnIn 2 S 4 / Bi heterojunction photodetector is a new type of photodetector, which uses different semiconductor materials to form a heterojunction. The built-in electric field formed between the two can promote the separation of photogenerated carriers, further improve the photoresponse characteristics of the photodetector, and achieve efficient detection of optical signals. Compared with traditional two-dimensional material photodetectors, heterojunction photodetectors show higher performance and wider application prospects;

[0042] The technical solution of this embodiment solves the technical problem that people have been eager to solve but have never been able to solve successfully;

[0043] This embodiment solves most of the research on ZnIn 2 S 4 In the field of thin-film solar cells and photocatalysis, there are few studies on its application as a photodetector, and the application of single ZnIn 2 S 4 Problems include limited light absorption capacity and fast carrier recombination rate.

[0044] This embodiment is based on ZnIn 2 S 4 The design and manufacture of / Bi heterojunction photodetectors has brought the following significant technological advances:

[0045] (1) Improving the performance of photodetectors: using ZnIn 2 S 4 The unique photoelectric properties of the Bi heterostructure can achieve a higher photoelectric response rate and spectral response range. This means that the detector can capture and convert light energy more effectively and improve the photoelectric conversion efficiency;

[0046] (2) Improve the stability and durability of the device: The heterojunction structure makes the device more stable and durable. This design reduces the performance degradation of the device during long-term use and prolongs its service life.

[0047] (3) Innovative preparation methods: Pulsed laser deposition has the advantages of precise control, large-area preparation, and no pollution. It does not require expensive and potentially risky precursors, and can effectively avoid the introduction of impurities and pollutants;

[0048] (4) Environmental friendliness and sustainability: The device materials themselves are non-toxic and environmental considerations are taken into account during the material preparation process, such as the use of non-toxic or low-toxic materials, making the entire production process more environmentally friendly and sustainable.

[0049] All technical features in this embodiment can be freely combined according to actual needs.

[0050] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

Claims

1. A high-performance photodetector based on ZnIn2S4 / Bi heterojunction, characterized in that: The following steps are involved: S1. Place the FTO conductive glass in a beaker containing acetone, anhydrous ethanol and deionized water in turn, and put it into an ultrasonic cleaner for cleaning. Clean for 20 minutes each, 2 to 3 times, to remove organic and inorganic pollutants on the surface of the FTO conductive glass. After cleaning, use a nitrogen air gun to blow dry the residual water on the surface of the FTO conductive glass in one direction to obtain an FTO conductive glass without any pollutants on the surface to ensure the purity of the coating. S2. Fix the cleaned FTO conductive glass and place it in the vacuum deposition chamber of the pulse laser deposition system. After closing the pulse laser deposition system, turn on the vacuum mechanical pump of the pulse laser deposition system to pump the vacuum degree in the deposition chamber to below 10Pa. Then turn on the solenoid valve and molecular pump of the pulse laser deposition system to further evacuate the vacuum degree in the deposition chamber to 10 -4 Pa level; S3. After reaching the vacuum level described in S2, open the gas cylinder of the pulse laser deposition system to introduce argon gas into the deposition chamber, and use the principle of glow discharge to perform plasma cleaning on the conductive glass to further remove pollutants and ensure the cleanliness of the deposition substrate. After cleaning for 10 minutes, close the gas cylinder of the pulse laser deposition system and wait for the molecular pump of the pulse laser deposition system to continue to pump the vacuum level in the deposition chamber to 10 -5 Pa level, finally reaching the ideal deposition conditions and obtaining the sample; S4, setting the distance between the sample and the ZnIn2S4 target to 5 cm, turning on the rotation switch of the sample and the ZnIn2S4 target in the pulsed laser deposition system, so that the film is formed uniformly and continuously during the deposition process; S5, preheating the solid laser of the pulse laser deposition system to perform a pulse laser deposition experiment; S6. After deposition, the ZnIn2S4 target is converted in situ through the external knob of the pulsed laser deposition system to ensure a high vacuum coating environment to avoid the introduction of impurities. Then ZnIn2S4 is vertically deposited on the Bi basis. After the deposition process is completed, the pulsed laser deposition system is turned off, and the sample is taken out after cooling to obtain a ZnIn2S4 / Bi heterojunction.

2. A high performance photodetector based on ZnIn2S4 / Bi heterojunction according to claim 1, characterized in that: The prepared ZnIn2S4 / Bi heterojunction is used as the anode working electrode, and the counter electrode platinum sheet, saturated calomel electrode and the configured hydroxide solution are used as electrolytes to form a photoelectrochemical photodetector. When the light source irradiates the working system, the photoelectric signal is captured by the photoelectrochemical workstation.

3. A high performance photodetector based on ZnIn2S4 / Bi heterojunction according to claim 1, characterized in that: The solid laser of the pulsed laser deposition system has an emission wavelength of 532nm, an output voltage of 760V, a pulse frequency of 4Hz, and a single laser pulse energy of about 480mJ.

4. A high performance photodetector based on ZnIn2S4 / Bi heterojunction according to claim 3, characterized in that: The solid laser of the pulsed laser deposition system is focused by a lens at an incident angle of 45° and irradiated onto the target surface for 30 minutes.

5. A high performance photodetector based on ZnIn2S4 / Bi heterojunction according to claim 2, characterized in that: The photocurrent density of the photoelectrochemical photodetector reaches 42.08 μA / cm 2 ,The photoresponsivity of the photoelectrochemical photodetector reaches 295.31μA / W.

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