Preparation method and application of lossless bismuth selenide film based on sodium chloride substrate

Abstract

The present invention provides a preparation method and application of a lossless bismuth selenide film based on a sodium chloride substrate, which belongs to the technical field of photoelectric material preparation, specifically: placing Bi2O3 powder and Bi2Se3 block with a mass ratio of 2 to 3:1 in the middle and upstream of a double-temperature zone tubular furnace, and placing a NaCl substrate with a (001) surface in the downstream of the double-temperature zone tubular furnace; evacuating the double-temperature zone tubular furnace to 0.1 Pa, flushing with argon gas, raising the temperatures of the middle and upstream and downstream to 500 to 700 ° C and 350 to 550 ° C respectively within 30 minutes, and obtaining a lossless bismuth selenide film of coherent epitaxial growth after 10 to 60 minutes. In a photoelectric detector, the lossless bismuth selenide film is adhered to a thermal release tape, the NaCl substrate is removed by dripping deionized water, and the thermal release tape is thermally released to achieve lossless and pollution-free transfer of the bismuth selenide film, and the device can achieve a photocurrent response from ultraviolet-visible-infrared.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric material preparation, and specifically relates to a preparation method and application of a lossless bismuth selenide film based on a sodium chloride substrate. Background Art

[0002] Two-dimensional materials are a new type of atomically thin materials without dangling bonds. They have attracted great interest due to their attractive properties, including thickness-dependent electronic band structure, tunable electronic and optoelectronic properties, good mechanical flexibility, and applications in ferroelectric properties.

[0003] The problems of optoelectronic devices based on two-dimensional materials include: poor light absorption of graphene, poor environmental stability of black phosphorus, and low carrier mobility of molybdenum disulfide. Bi2O2Se has good air stability and high carrier mobility (>2000cm 2 ·V -1 ·S -1 ) and a lower subthreshold swing (SS, ≈65mVdec -1 ), which has high sensitivity and strong photoelectric response over a wide spectral range, making it a candidate material for the next generation of photodetectors.

[0004] At present, Bi2O2Se is mainly synthesized by chemical vapor deposition (CVD), physical vapor deposition (PVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD) and solution (wet chemistry) methods. CVD and PVD can achieve millimeter-sized Bi2O2Se growth on mica substrates, but it is difficult to transfer to other target substrates. Bi2O2Se obtained by MBE and PLD methods usually requires ultra-high vacuum conditions and expensive equipment, which limits its large-scale industrial application. The Bi2O2Se crystals obtained by the solution method are small in size and poor in quality. At the same time, these methods all face a common problem. In the process of material transfer, corrosive agents such as hydrofluoric acid need to be used, which corrodes Bi2O2Se greatly, causing a large number of defects in the material and greatly reducing the carrier mobility of the material.

[0005] Based on the CVD method, a non-destructive Bi2O2Se film that is easily transferred to various other target substrates is proposed, which is of great significance for the development of photodetectors. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for preparing a lossless bismuth selenide thin film based on a sodium chloride substrate and its application. The growth orientation of the lossless bismuth selenide thin film is consistent and it can be easily transferred to other target substrates. It has the advantages of low cost, wide spectrum and high response when used in photodetectors.

[0007] A method for preparing a lossless bismuth selenide thin film based on a sodium chloride substrate, characterized in that it comprises the following steps:

[0008] Step A1: cutting a sodium chloride (NaCl) crystal according to the (001) plane;

[0009] Step A2: Weigh Bi2O3 powder and Bi2Se3 block with a mass ratio of 2 to 3:1, place them in a porcelain boat in the middle and upper reaches of a double-temperature zone tube furnace, and place a NaCl substrate with the (001) surface facing upward in a quartz boat in the downstream of the double-temperature zone tube furnace;

[0010] Step A3: Evacuate the double-temperature zone tubular furnace to 0.1 Pa, and flush it with argon three times. Continue to introduce argon as a carrier gas. Within 30 minutes, raise the temperatures of the upstream and downstream of the double-temperature zone tubular furnace to 500-700°C and 350-550°C, respectively. After keeping warm for 10-60 minutes, stop introducing argon. After cooling to room temperature, a lossless bismuth selenide film based on a sodium chloride substrate is obtained.

[0011] Furthermore, the flow rate of the argon gas is 50-150 sccm.

[0012] Furthermore, the lossless bismuth oxide selenide film is grown by a coherent epitaxial method with consistent epitaxial surface symmetry, and has high orientation consistency.

[0013] The present invention also provides an application of the lossless bismuth selenium oxide film based on a sodium chloride substrate in a photoelectric detector, and specifically provides a method for preparing a photoelectric detector based on the lossless bismuth selenium oxide film, which is characterized by comprising the following steps:

[0014] Step B1: Transferring the Bi2O2Se film to the target substrate: A layer of thermal release tape is adhered to the upper surface of the lossless bismuth oxyselenide film based on the sodium chloride substrate as a transfer intermediate layer, and deionized water is added to gradually dissolve the NaCl substrate to obtain a Bi2O2Se film attached to the thermal release tape; then, the opposite side of the thermal release tape attached with the Bi2O2Se film is adhered to the target substrate, the viscosity of the transfer intermediate layer is released, and it is peeled off from the Bi2O2Se film to obtain a lossless Bi2O2Se film transferred to the target substrate;

[0015] Step B2: Spin-coat a layer of methyl methacrylate (PMMA) on the lossless Bi2O2Se film and dry it, construct an electrode pattern using electron beam lithography, and deposit metal electrodes by thermal evaporation to obtain a photodetector based on the lossless bismuth selenide film.

[0016] Furthermore, the thermal release tape is a tape made of heat-sensitive adhesive, which has a certain adhesive force at room temperature and loses its adhesive force after heating. Since it has less residue and does not contaminate the adherend, it can be used for simple peeling and transfer of two-dimensional materials; preferably, the thermal release tape is polydimethylsiloxane (PDMS), which loses its viscosity at 60°C.

[0017] Furthermore, the viscosity of the transfer intermediate layer is released by keeping the temperature at 60 to 80° C. for 5 to 10 minutes.

[0018] Furthermore, the target substrate is a SiO2 / Si substrate, and the thickness of SiO2 is 280nm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention proposes a method for preparing a lossless bismuth oxide selenide thin film based on a sodium chloride substrate. By using a CVD method, a lossless Bi2O2Se thin film with a (001) orientation is co-epitaxially grown on a (001) surface NaCl substrate. Since NaCl and Bi2O2Se have high lattice adaptability and high consistency in growth orientation, grain boundary-free, large-area continuous, high-quality thin film growth can be achieved.

[0021] 2. Due to the solubility of the NaCl substrate, after the lossless Bi2O2Se film is adhered to the transfer intermediate layer, the NaCl substrate can be removed by simply adding deionized water, and then the adhesiveness of the thermal release tape is released, thereby achieving lossless and pollution-free transfer of the Bi2O2Se film. The obtained film crystal is defect-free, and the transfer method is economical, simple and easy;

[0022] 3. The present invention applies the transferred lossless bismuth selenide oxide film to a photodetector to achieve a photocurrent response from ultraviolet to visible to infrared, with high mobility and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of a method for preparing a lossless bismuth oxide selenide thin film based on a sodium chloride substrate proposed in Example 1 of the present invention;

[0024] Figure 2 The crystal structure diagram of NaCl and Bi2O2Se in Example 1 of the present invention;

[0025] Figure 3 This is an optical picture of the growth of the lossless Bi2O2Se film obtained in Example 1 of the present invention;

[0026] Figure 4 This is a high resolution X-ray diffraction (HRXRD) characterization spectrum of the lossless Bi2O2Se film obtained in Example 1 of the present invention;

[0027] Figure 5 This is an atomic force microscope image of the damage-free Bi2O2Se film obtained in Example 1 of the present invention;

[0028] Figure 6 This is a transmission electron microscope characterization picture of the lossless Bi2O2Se film obtained in Example 1 of the present invention; wherein, Figure 6 (a) is a high-resolution atomic imaging image; Figure 6 (b) is the selected area electron diffraction image;

[0029] Figure 7 Schematic diagram of the transfer method of the lossless Bi2O2Se film in Example 2 of the present invention;

[0030] Figure 8 This is a comparison of optical photographs of the lossless Bi2O2Se film before and after transfer in Example 2 of the present invention; wherein, Figure 8 (a) is the picture before transfer; Figure 8 (b) is the image after transfer;

[0031] Fig. 9 The transfer curve and corresponding carrier mobility of the FET (field effect transistor) of the lossless Bi2O2Se thin film in the dark state in Example 2 of the present invention;

[0032] Fig.10 The photoelectric response curve of the photoelectric detector based on the lossless bismuth selenide oxide thin film obtained in Example 2 of the present invention under the incidence of light of different wavelengths; wherein, Fig.10 (a) is the IV curve of 405nm wavelength light; Fig.10 (b) is the time-resolved photoresponse curve of 405 nm wavelength light; Fig.10 (c) is the IV curve of 532nm wavelength light; Fig.10 (d) is the time-resolved photoresponse curve of 532 nm wavelength light; Fig.10 (e) is the IV curve of 808nm wavelength light; Fig.10 (f) is the time-resolved photoresponse curve of 808 nm wavelength light; Fig.10 (g) is the IV curve of 1550nm wavelength light; Fig.10 (h) is the time-resolved photoresponse curve of 1550 nm wavelength light. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0034] Example 1

[0035] This example prepares a lossless bismuth selenide film based on a sodium chloride substrate. Figure 1 As shown, the following steps are included:

[0036] Step A1: Clean the experimental equipment and cut the NaCl crystal according to the (001) plane;

[0037] Step A2: Weigh 20 mg of Bi2O3 powder and 10 mg of Bi2Se3 block, place them in a porcelain boat in the middle and upper reaches of a double-temperature zone tube furnace, and place a NaCl substrate with the (001) surface facing upward in a quartz boat in the downstream of the double-temperature zone tube furnace;

[0038] Step A3: Evacuate the double-temperature zone tubular furnace to 0.1 Pa, and introduce 100-150 sccm of argon gas for flushing three times, and continue to introduce argon gas as a carrier gas to maintain the pressure in the double-temperature zone tubular furnace at atmospheric pressure. Within 30 minutes, raise the temperatures of the upstream and downstream of the double-temperature zone tubular furnace to 650°C and 500°C, respectively. After keeping warm for 30 minutes, stop introducing argon gas, and after naturally cooling to room temperature, a lossless bismuth selenide film based on a sodium chloride substrate is obtained.

[0039] Figure 2 The crystal structure diagram of NaCl and Bi2O2Se shows that the lattice constant of NaCl on the (001) plane is The lattice constant of Bi2O2Se oriented (001) is The two have perfectly matched lattice constants, which allows for co-epitaxial growth of Bi2O2Se films on NaCl substrates.

[0040] Figure 3 This is an optical picture of the growth of the lossless Bi2O2Se film obtained in this embodiment. It can be seen that the shape of the lossless Bi2O2Se film is almost a regular square, there is no grain boundary between them, the domain size is about 20μm, and the area is relatively large.

[0041] Figure 4 This is the HRXRD characterization picture of the lossless Bi2O2Se film obtained in this example. There are obvious peaks at four angles, indicating that the lossless Bi2O2Se film grows along the same direction. At the same time, the angle range is within 0.4°, indicating that the lossless Bi2O2Se film has good crystallinity and grows coherently with the NaCl growth substrate.

[0042] Figure 5 This is an atomic force microscope picture of the lossless Bi2O2Se film obtained in this example. The thickness of the lossless Bi2O2Se film is 7nm, and its surface is atomically flat.

[0043] Figure 6 This is a transmission electron microscope characterization picture of the lossless Bi2O2Se film obtained in this example. Figure 6 The high-resolution image (a) shows that the (110) interplanar spacing of the lossless Bi2O2Se film is Theoretical value of the interplanar spacing with the (110) plane of Bi2O2Se crystal Consistency; Figure 6 The selected area electron diffraction image (b) shows that the lossless Bi2O2Se film synthesized in this example belongs to the tetragonal crystal plane family.

[0044] Example 2

[0045] Based on the lossless bismuth selenide film based on sodium chloride substrate obtained in Example 1, this example prepares a photodetector, and the process flow is as follows: Figure 7 As shown, the following steps are included:

[0046] Step B1: Transferring the lossless Bi2O2Se film to a SiO2 / Si substrate, wherein the thickness of SiO2 is 280 nm: a layer of PDMS is adhered to the upper surface of the lossless bismuth selenide film based on the sodium chloride substrate as a transfer intermediate layer, and deionized water is added dropwise to gradually dissolve the NaCl substrate to obtain a Bi2O2Se film attached to the PDMS; then, the opposite surface of the PDMS to which the lossless Bi2O2Se film is attached is adhered to the SiO2 / Si substrate, and after being kept at 80°C for 10 minutes, the viscosity of the transfer intermediate layer is released, and the transfer intermediate layer is peeled off from the lossless Bi2O2Se film to obtain a lossless Bi2O2Se film transferred to the SiO2 / Si substrate;

[0047] Step B2: Spin coat a layer of PMMA on the lossless Bi2O2Se film at a rotation speed of 1500 r / s for 60 seconds, and dry it on a heating table at 150°C for 5 minutes. Define the electrode pattern using electron beam lithography, immerse it in photoresist developer for 12 seconds to display the electrode pattern, and deposit Cr (5nm) / Au (50nm) metal film by thermal evaporation to obtain a photodetector based on bismuth oxide selenide film.

[0048] Figure 8 This is a comparison of optical photographs of the lossless Bi2O2Se film before and after transfer in this embodiment. Figure 8 (a) is the picture before transfer. Figure 8 (b) is the picture after transfer, which shows that the position and orientation of the lossless Bi2O2Se nanosheets before and after transfer remain highly consistent, and almost 100% transfer success rate is achieved.

[0049] Fig. 9 The transfer curve and corresponding carrier mobility of the FET of the lossless Bi2O2Se film in the dark state. It can be seen that the room temperature carrier mobility of the obtained Bi2O2Se film can reach 501.5 cm 2 ·V -1 ·S -1 .

[0050] In this embodiment, the obtained photoelectric detector based on the lossless bismuth selenium oxide thin film was subjected to photoelectric testing. Light with wavelengths of 405nm (purple light), 532nm (green light), 808nm (near infrared) and 1550nm (infrared) were used as simulated light sources to test the photoelectric response performance of the photoelectric detector under different light power conditions. The results are shown in FIG. Fig.10 As shown, it has a strong photocurrent response from ultraviolet to visible to infrared, excellent detection performance and wide application.

Claims

1. A method for preparing a lossless bismuth selenide thin film based on a sodium chloride substrate, characterized in that: The following steps are involved: Step A1: cutting the NaCl crystal according to the (001) plane; Step A2: Weigh Bi2O3 powder and Bi2Se3 block with a mass ratio of 2 to 3:1, place them in a porcelain boat in the middle and upper reaches of a double-temperature zone tube furnace, and place a NaCl substrate with the (001) surface facing upward in a quartz boat in the downstream of the double-temperature zone tube furnace; Step A3: Evacuate the double-temperature zone tubular furnace to 0.1 Pa, and flush it with argon three times. Continue to introduce argon as a carrier gas. Within 30 minutes, raise the temperatures of the middle and upstream and downstream of the double-temperature zone tubular furnace to 650°C and 500°C, respectively. After keeping warm for 30 minutes, stop introducing argon. After cooling to room temperature, a lossless bismuth selenide thin film based on a sodium chloride substrate is obtained, which is suitable for the preparation of photodetectors.

2. The method for preparing a lossless bismuth selenide thin film based on a sodium chloride substrate according to claim 1, characterized in that: The flow rate of the argon gas is 50-150 sccm.

3. A method for preparing a photodetector based on a lossless bismuth selenide film, characterized in that: The following steps are involved: Step B1: transferring the lossless bismuth selenide film based on a sodium chloride substrate obtained by the preparation method as described in claim 1 to a target substrate: adhering a layer of thermal release tape on the upper surface of the lossless bismuth selenide film based on a sodium chloride substrate, and gradually dissolving the NaCl substrate by dripping deionized water to obtain a lossless Bi2O2Se film attached to the thermal release tape; then adhering the opposite side of the thermal release tape to which the lossless Bi2O2Se film is attached to the target substrate, releasing the viscosity of the thermal release tape, and peeling it off from the lossless Bi2O2Se film to obtain a lossless Bi2O2Se film transferred to the target substrate; Step B2: Spin-coat a layer of PMMA on the lossless Bi2O2Se film and dry it, construct an electrode pattern using electron beam lithography, and deposit metal electrodes by thermal evaporation to obtain a photodetector based on the lossless bismuth selenide film.

4. The method for preparing a photodetector based on a lossless bismuth selenide oxide thin film according to claim 3, characterized in that: The thermal release tape is a tape made of a heat-sensitive adhesive, including PDMS.

5. The method for preparing a photodetector based on a lossless bismuth selenide oxide thin film according to claim 3, characterized in that: The adhesiveness of the heat release tape is released by keeping the temperature at 60 to 80°C for 5 to 10 minutes.

6. The method for preparing a photodetector based on a lossless bismuth selenide oxide thin film according to claim 3, characterized in that: The target substrate is a SiO2 / Si substrate.

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