Two-dimensional indium selenide crystal material, preparation method thereof and field effect transistor

Abstract

The invention relates to the field of preparation of two-dimensional materials, in particular to a preparation method of a two-dimensional indium selenide crystal material. According to the method provided by the invention, the centimeter-level two-dimensional indium selenide crystal material is synthesized through short-distance chemical vapor deposition, the beta-phase two-dimensional indium selenide crystal material can be obtained by taking In2O3 and elemental selenium as target materials, and the beta '-phase two-dimensional indium selenide crystal material can be obtained by taking In2O3, InSe and elemental selenium as target materials. The alpha-phase two-dimensional indium selenide crystal material can be obtained by releasing stress by taking the beta '-phase two-dimensional indium selenide crystal material as a precursor. The method provided by the invention can realize the synthesis of beta, beta 'and alpha phase two-dimensional indium selenide crystal materials with large area and high crystal phase purity. Experiments show that the centimeter-level pure beta, beta'and alpha-phase two-dimensional indium selenide crystal material is successfully synthesized through the method, and a field effect transistor prepared from the material is high in performance and has the potential of serving as a memory storage device.

Description

[0001] This application is a divisional application of the Chinese patent application submitted to the China Patent Office on June 1, 2022, with application number 202210617423.2, and invention name “A method for preparing a two-dimensional indium selenide crystal material”, all contents of which are incorporated by reference in this application. Technical Field

[0002] The invention relates to the field of preparation of two-dimensional materials, and specifically to a method for preparing a two-dimensional indium selenide crystal material. Background Art

[0003] Two-dimensional ferroelectric semiconductors with polarization conversion effects can be applied to a variety of new devices, such as ferroelectric field effect transistors, non-volatile memory, integrated storage and computing chips, or brain-like computing chips [Nat. Electron.3, 588-597 (2020)]. Unlike the traditional von Neumann system, two-dimensional ferroelectric transistors integrate both logic operations and memory storage, and have the potential to reduce device size and energy consumption in the future. So far, among the two-dimensional ferroelectric semiconductors reported (such as In 2 Se 3 , SnTe, CuInP 2 S 6 , MoTe 2 and SnS), In 2 Se 3 It has attracted wide attention due to its multiple phases, among which the β′ phase In 2 Se 3 It has room temperature in-plane ferroelectric and antiferroelectric structures, ferroelasticity, and high theoretical mobility [Phys. Rev. Lett. 125, 047601 (2020)]; α-phase In 2 Se 3 With a diameter of about 488 cm 2 V -1 s -1 Excellent carrier mobility [Nat. Commun. 8, 14956 (2017); Nat. Electron. 2, 580-586 (2019)], suitable band gap (1.39 eV), and room temperature out-of-plane and in-plane ferroelectricity as thin as a monolayer limit [Nano Lett. 18, 1253-1258 (2018)]. 2 Se 3 The multiphase and ferroelectric properties provide many opportunities for regulating ferroelectric structure and properties, making two-dimensional In 2 Se 3 Become a suitable candidate for application in memory transistors and other new devices.

[0004] Although the two-dimensional 2 Se 3 It has attractive application potential, but large-area 2D In 2 Se 3 The synthesis of thin films remains a major challenge. 2 Se 3 Complex phases (α, β, β′, γ) and low phase transition temperatures (β′→β phase transition at 250°C, α→β phase transition at 270°C) often lead to the coexistence of multiple phases during the growth process, making it difficult to obtain pure phase In. 2 Se 3 Thin films [Nano Lett. 13, 3501–3505 (2013); Chem. Mater. 31, 10143 (2019)]. Especially β, β′ and α phase In 2 Se 3 The energy difference between them is small, so it is easy to stimulate the phase transition between them.

[0005] For β-phase In 2 Se 3 Although there have been reports on the synthesis of films by chemical vapor deposition (CVD), their size is still limited to less than a few hundred microns [Nanoscale 12, 20189-20201 (2020)]. This is because the distance between the precursor and the substrate in the currently reported CVD method is relatively far (generally more than 10 cm), making it difficult to obtain a stable gas supply, and the concentration gradient distribution of the evaporated gaseous precursor is uneven, making it difficult to obtain large-area continuous growth of thin films on the substrate.

[0006] For β′ phase In 2 Se 3 , which is the β-phase In 2 Se 3 A metastable phase of β′-In was discovered in a mixed phase as early as 1975 [Phys. Status Solidi (a) 3, 299-314 (1975)], but so far, large-scale β′-In 2 Se 3 Thin films cannot yet be synthesized directly.

[0007] For α-phase In 2 Se 3 So far, only a few research groups have been able to directly obtain two-dimensional α-In by CVD. 2 Se 3, but their sizes are all below 100 microns, far from meeting the requirements of large-scale integration [2D Mater. 5, 035026 (2018)]. Summary of the invention

[0008] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing a two-dimensional indium selenide crystal material. The method provided by the present invention prepares a two-dimensional indium selenide crystal material with a large area and high crystal phase purity.

[0009] The present invention provides a method for preparing a two-dimensional indium selenide crystal material, which is characterized by comprising the following steps: 2 O 3 Chemical vapor deposition was carried out with selenium as target to obtain pure β-phase two-dimensional indium selenide crystal material.

[0010] Specifically, the present invention is based on In 2 O 3 and selenium as target materials, chemical vapor deposition is performed in a reducing gas atmosphere using a chemical vapor deposition device to obtain a pure β-phase two-dimensional indium selenide crystal material on a substrate. 2 O 3 and selenium powder as target materials, chemical vapor deposition is carried out in a reducing gas atmosphere in a horizontal tube furnace, the horizontal tube furnace is divided into an upstream temperature zone and a downstream temperature zone, the reducing gas flows from the upstream temperature zone to the downstream temperature zone, the selenium powder target material is located in the upstream temperature zone, the In 2 O 3 The target material and the substrate are located in the downstream temperature zone, and a pure β-phase two-dimensional indium selenide crystal material is obtained on a fluorophlogopite mica substrate.

[0011] In one embodiment, the reducing gas is H 2 and N 2 The H 2 The volume fraction of the reducing gas is 5%; the flow rate of the reducing gas is 30-100 sccm. In one embodiment, the chemical vapor deposition is performed at 1 atmosphere. In one embodiment, the temperature of the selenium single target during chemical vapor deposition is 250-300°C; the In 2 O 3 The temperature of the target during chemical vapor deposition is 600~760℃.

[0012] In one embodiment, during chemical vapor deposition, the In 2 O 3The vertical distance between the target and the substrate is 1-3 mm. The ultra-short transmission distance between the target and the substrate of the present invention provides a stable, uniform and continuous gas source supply for substrate deposition of the target, thereby obtaining a large-sized pure β-phase two-dimensional indium selenide crystal material.

[0013] In the present invention, under the reduction effect of reducing gas, In 2 O 3 Chemical vapor deposition is carried out by controlling In 2 O 3 The distance between the target and the substrate was reduced, and centimeter-level pure β-phase two-dimensional indium selenide crystal material was obtained on the substrate.

[0014] The present invention also provides a method for preparing a two-dimensional indium selenide crystal material. 2 O 3 , InSe and selenium as target materials for chemical vapor deposition to obtain pure β′ phase two-dimensional indium selenide crystal material. 2 O 3 , InSe and selenium as target materials, chemical vapor deposition is carried out in a reducing gas atmosphere using a chemical vapor deposition equipment to obtain a pure β′ phase two-dimensional indium selenide crystal material on a substrate.

[0015] In certain embodiments of the present invention, the present invention is based on In 2 O 3 , InSe and selenium powder as target materials, chemical vapor deposition is carried out in a horizontal tube furnace in a reducing gas atmosphere, the horizontal tube furnace is divided into an upstream temperature zone and a downstream temperature zone, the reducing gas flows from the upstream temperature zone to the downstream temperature zone, the selenium powder target material is located in the upstream temperature zone, the InSe and selenium powder target material is located in the upstream temperature zone, 2 O 3 The target material, InSe target material and fluorophlogopite substrate are located in the downstream temperature zone, and a pure β′ phase two-dimensional indium selenide crystal material is obtained on the fluorophlogopite substrate. The present invention uses InSe as a growth promoter, which can inhibit the nucleation of the β phase, promote the nucleation growth of the β′ phase, and realize the preparation of a pure β′ phase two-dimensional indium selenide crystal material.

[0016] In one embodiment, the In 2 O 3 The mass ratio of InSe to InSe is 1 to 10:10. 2 O 3 The ratio of InSe target material to β′-phase two-dimensional indium selenide crystal material is increased, and pure β′-phase two-dimensional indium selenide crystal material is obtained.

[0017] In one embodiment, the reducing gas is H 2 and N 2 The H2 The volume fraction of the reducing gas is 5%; the flow rate of the reducing gas is 30-100 sccm. In one embodiment, the chemical vapor deposition is performed at 1 atmosphere. In one embodiment, the temperature of the selenium single target during chemical vapor deposition is 250-300°C; the In 2 O 3 The temperature for chemical vapor deposition with InSe target is 600~760℃.

[0018] In one embodiment, during chemical vapor deposition, the In 2 O 3 The vertical distance between the target and the substrate is 1-3 mm. The ultra-short transmission distance between the target and the substrate of the present invention also provides a stable, uniform and continuous gas source supply for substrate deposition of the target, thereby obtaining a large-sized pure β′ phase two-dimensional indium selenide crystal material.

[0019] The present invention uses In under the action of reducing gas. 2 O 3 , InSe and selenium as targets for chemical vapor deposition. 2 O 3 The ratio of InSe to β phase was increased, the nucleation of β′ phase was promoted, and the centimeter-level pure β′ phase two-dimensional indium selenide crystal material was obtained on the substrate by combining the short-distance vapor deposition method.

[0020] The present invention also obtains a pure α-phase two-dimensional indium selenide crystal material by completely releasing the stress of the above-mentioned pure β′-phase two-dimensional indium selenide crystal material. Specifically, the present invention transfers the pure β′-phase two-dimensional indium selenide crystal material to a flexible or rough substrate, completely releasing its stress, thereby obtaining a pure α-phase two-dimensional indium selenide crystal material through a phase change. Compared with the situation in the prior art where the chemical vapor deposition method is difficult to directly grow and obtain an α-phase two-dimensional indium selenide crystal material, the present invention uses a centimeter-level pure β′-phase two-dimensional indium selenide crystal material as a precursor, transfers it to a flexible or rough substrate to release the stress, and obtains a large-area pure α-phase two-dimensional indium selenide crystal material.

[0021] In one embodiment, the flexible or rough substrate is selected from PET, copper sheet or uneven silicon sheet. In one embodiment, after the pure β′ phase two-dimensional indium selenide crystal material is transferred to the copper sheet through polymethyl methacrylate (PMMA), its stress is completely released to obtain a pure α phase two-dimensional indium selenide crystal material. In one embodiment, after the pure β′ phase two-dimensional indium selenide crystal material is transferred to PET through PMMA, it is repeatedly bent and its stress is completely released to obtain a pure α phase two-dimensional indium selenide crystal material.

[0022] The present invention also provides a two-dimensional indium selenide crystal material prepared by the above-mentioned preparation method. The two-dimensional indium selenide crystal material is a high-quality crystal with high electron mobility, and its β′ and α phases have ferroelectric effect. The thinnest can reach a single-layer limit of 0.9 nm, and has broad prospects in the application of ferroelectric transistors and ferroelectric memory devices.

[0023] The present invention also provides a field effect transistor, comprising the two-dimensional indium selenide crystal material prepared by the above preparation method or the above two-dimensional indium selenide crystal material. The field effect transistor provided by the present invention has a ferroelectric effect and high performance.

[0024] The preparation of large-area pure phase-two-dimensional InSe crystal materials is crucial for the study of basic physical properties and the application of large-scale electronic devices. Therefore, the realization of phase-controlled preparation of large-area two-dimensional InSe crystal materials is a key technical issue in the research and application of two-dimensional InSe crystal materials.

[0025] The invention provides a method for preparing a two-dimensional indium selenide crystal material, using a short-distance chemical vapor deposition method to prepare a two-dimensional indium selenide crystal material. 2 O 3 Pure β-phase two-dimensional indium selenide crystal material can be obtained by using In 2 O 3 , InSe and selenium as target materials can obtain pure β′ phase two-dimensional indium selenide crystal materials, and pure α phase two-dimensional indium selenide crystal materials can be obtained by releasing stress using pure β′ phase two-dimensional indium selenide crystal materials as precursors. The method provided by the present invention can realize the synthesis of β, β′ and α phase two-dimensional indium selenide crystal materials, and the obtained two-dimensional indium selenide crystal materials have a large area and high crystal phase purity. Experiments show that the method of the present invention can successfully synthesize centimeter-level pure β, β′ and α phase two-dimensional indium selenide crystal materials, and the field effect transistor prepared by the method has ferroelectric effect, high performance, and has the potential to be used as a memory storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 To prepare centimeter-scale two-dimensional β-phase In 2 Se 3 Schematic diagram of the device for thin films of crystalline materials;

[0027] Figure 2 To prepare centimeter-scale two-dimensional β′ phase In 2 Se 3 Schematic diagram of the device for thin films of crystalline materials;

[0028] Figure 3 To prepare centimeter-scale two-dimensional α-phase In 2 Se 3 Schematic diagram of a thin film of crystalline material;

[0029] Figure 4 Schematic diagram of the preparation of β, β′ and α phase two-dimensional indium selenide crystal materials;

[0030] Figure 5 The centimeter-scale two-dimensional β-phase In prepared in Example 1 2 Se 3 Digital camera photographs of the film;

[0031] Figure 6 The centimeter-scale two-dimensional β′ phase In prepared in Example 2 2 Se 3 Digital camera photographs of the film;

[0032] Figure 7 The centimeter-scale two-dimensional α-phase In prepared in Example 3 2 Se 3 Digital camera photographs of the film;

[0033] Figure 8 The centimeter-scale two-dimensional β-phase In prepared in Example 1 2 Se 3 Optical micrographs of thin films;

[0034] Fig. 9 The centimeter-scale two-dimensional β′ phase In prepared in Example 2 2 Se 3 Optical micrographs of thin films;

[0035] Fig.10 The centimeter-scale two-dimensional α-phase In prepared in Example 3 2 Se 3 Optical micrographs of thin films;

[0036] Fig.11 The three phases of In prepared in Examples 1 to 3 2 Se 3 Raman spectra of thin films;

[0037] Fig.12 The centimeter-scale β-phase In prepared in Example 1 2 Se 3 Atomic force microscopy images of the film;

[0038] Fig.13 For the two-dimensional β′ phase In 2 Se 3 Transfer characteristic hysteresis curves of thin film field effect transistors at different bias voltages;

[0039] Fig.14 Two-dimensional α-phase In 2 Se 3 Transfer characteristic hysteresis curve of thin film field effect transistor under different gate voltage scanning ranges. DETAILED DESCRIPTION

[0040] The present invention discloses a method for preparing a two-dimensional indium selenide crystal material. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0041] The present invention will be further described below in conjunction with embodiments:

[0042] Example 1

[0043] Preparation of two-dimensional β-phase In using a horizontal tube furnace 2 Se 3 The film, wherein the horizontal tube furnace is divided into an upstream temperature zone and a downstream temperature zone, about 60 mg of Se powder is placed in a ceramic boat at the upstream temperature zone of the horizontal tube furnace and spread evenly; about 6 mg of In 2 O 3 The powder was placed in a quartz boat at the downstream temperature zone and spread evenly. 3 AlSi 3 O 10 F 2 ) as the substrate and placed on the In 2 O 3 The powder is directly above the substrate, and the vertical distance between the source material and the substrate is controlled within a small range (1~3 mm). Figure 1 As shown, Figure 1 To prepare centimeter-scale two-dimensional β-phase In 2 Se 3 Schematic diagram of the device for crystalline material thin film, where 1 is a tube furnace, 2 is Se powder, and 3 is In 2 O 3 Powder, 4 is mica substrate.

[0044] The horizontal tube furnace containing the active materials is pre-evacuated and then filled with H 2 and N 2 The mixed gas was heated to 1 atmosphere and residual oxygen was removed by gas washing. The target temperature of temperature zone 2 was set to 300°C and the target temperature of temperature zone 3 was set to 660°C. The temperature was increased at a rate of 30°C / min. After reaching the target temperature, the temperature was kept for 30 min for reaction. During the reaction, 30 sccm of H 2 and N 2After the reaction, the carrier gas remained unchanged, and the product was cooled to room temperature with the furnace, and a two-dimensional pure β-phase In was obtained on the mica substrate. 2 Se 3 film.

[0045] Example 2

[0046] Preparation of two-dimensional β′ phase In by horizontal tube furnace 2 Se 3 The film, wherein the horizontal tube furnace is divided into an upstream temperature zone and a downstream temperature zone, about 60 mg of Se powder is placed in a ceramic boat at the upstream temperature zone of the horizontal tube furnace and spread evenly; about 6 mg of In with a mass ratio of 10:10 is placed in a ceramic boat. 2 O 3 The mixed powder of InSe and MgSe was placed in a quartz boat at the downstream temperature zone and spread evenly. 3 AlSi 3 O 10 F 2 ) as the substrate and placed on the In 2 O 3 The powder is directly above the substrate, and the vertical distance between the source material and the substrate is controlled within a small range (1~3 mm). Figure 2 As shown, Figure 2 To prepare centimeter-scale two-dimensional β′ phase In 2 Se 3 Schematic diagram of the device for crystalline material thin film, where 1 is a tube furnace, 2 is Se powder, and 3 is In 2 O 3 and InSe mixed powder, 4 is a mica substrate.

[0047] The horizontal tube furnace containing the active materials is pre-evacuated and then filled with H 2 and N 2 The mixed gas was heated to 1 atmosphere and residual oxygen was removed by gas washing. The target temperature of temperature zone 2 was set to 300°C and the target temperature of temperature zone 3 was set to 660°C. The temperature was increased at a rate of 30°C / min. After reaching the target temperature, the temperature was kept for 30 min for reaction. During the reaction, 30 sccm of H 2 and N 2 After the reaction, the carrier gas remained unchanged, and the product was cooled to room temperature with the furnace, and a two-dimensional β′ phase In was obtained on the mica substrate. 2 Se 3 film.

[0048] Example 3

[0049] Metastable β′ phase In2 Se 3 The film can undergo a phase transition to the more stable α-phase In by releasing the stress. 2 Se 3 First, the two-dimensional β′ phase In grown in Example 2 2 Se 3 The mica sample of the film was coated with a layer of PMMA solution by a spin coater at a speed of 3000 r / min, and then the sample with PMMA was baked on a hot plate at 100°C for 5 minutes to evaporate the organic solvent in PMMA, so that PMMA becomes a solid film. Then the sample was immersed in deionized water, and the surface tension of water was used to make the two-dimensional β′ phase In 2 Se 3 The PMMA film and mica sheet of the film are separated. 2 Se 3 The PMMA film of the film was transferred to the copper foil and baked on a hot plate at 45°C for 10 minutes to completely evaporate the water. After dissolving the PMMA with acetone solution, In 2 Se 3 The film was transferred to copper foil to directly obtain a large area of ​​two-dimensional α-phase In 2 Se 3 Film. Figure 3 As shown, Figure 3 To prepare centimeter-scale two-dimensional α-phase In 2 Se 3 Schematic diagram of a thin film of crystalline material.

[0050] Based on the description of Examples 1 to 3, the present invention obtains a β or β′ phase two-dimensional indium selenide crystal material on a mica substrate by short-distance vapor deposition, and uses the β′ phase two-dimensional indium selenide crystal material as a precursor to release stress and transfer the phase to an α phase two-dimensional indium selenide crystal material, as shown in the schematic diagram Figure 4 As shown, Figure 4 Schematic diagram of the preparation of β, β′ and α phase two-dimensional indium selenide crystal materials.

[0051] Example 4

[0052] The difference from Example 3 is that the two-dimensional β′ phase In 2 Se 3 The PMMA film of the thin film is transferred to a flexible PET substrate. After being transferred to the PET substrate, the PET substrate is bent repeatedly several times to make the β′ phase In 2 Se 3 The stress of the substrate is completely released, and finally a large area of ​​two-dimensional α-phase In is obtained on the PET substrate. 2 Se 3 film.

[0053] Example 5

[0054] The In of the three phases prepared in Examples 1 to 3 was recorded by a digital camera. 2 Se 3 The macroscopic morphology of the film is shown in Figure 2. Figures 5 to 7 As shown, Figure 5 The centimeter-scale two-dimensional β-phase In prepared in Example 1 2 Se 3 Digital camera photos of the film, Figure 6 The centimeter-scale two-dimensional β′ phase In prepared in Example 2 2 Se 3 Digital camera photos of the film, Figure 7 The centimeter-scale two-dimensional α-phase In prepared in Example 3 2 Se 3 Digital camera photo of the film. Figures 5 to 7 It can be seen that In grown on transparent mica sheets 2 Se 3 The films are all about 1 cm in size, dark red in color, and still transparent.

[0055] The In phases of the three phases prepared in Examples 1 to 3 were observed using an optical microscope. 2 Se 3 The film was characterized by microstructure. Figures 8-10 As shown, Figure 8 The centimeter-scale two-dimensional β-phase In prepared in Example 1 2 Se 3 Optical micrographs of thin films. Fig. 9 The centimeter-scale two-dimensional β′ phase In prepared in Example 2 2 Se 3 Optical micrographs of thin films. Fig.10 The centimeter-scale two-dimensional α-phase In prepared in Example 3 2 Se 3 Optical micrograph of the film. Figures 8-10 It can be seen that the three phases of In 2 Se 3 The films are continuous and large in size.

[0056] The three phases of In prepared in Examples 1 to 3 2 Se 3 The film was analyzed by Raman spectroscopy. Fig.11 As shown, Fig.11 The three phases of In prepared in Examples 1 to 3 2 Se 3 Raman spectrum of the film. Fig.11 It can be seen that the Raman vibration peaks of each phase correspond well to the literature.

[0057] The β-phase In prepared in Example 1 2 Se 3 The film was observed using an atomic force microscope. Fig.12 As shown, Fig.12 The β-phase In prepared in Example 1 2 Se 3 Atomic force microscopy image of the film. Fig.12 It can be seen that the β phase In 2 Se 3 The film is continuous, and the surface is flat without protrusions and particles. Its thickness is 0.9 nm. This thickness has reached In 2 Se 3 The thickness limit is a single layer of In 2 Se 3 film.

[0058] Example 6

[0059] The three phases of In obtained in Examples 1 to 3 were 2 Se 3 The films were transferred to the surface of 300 nm SiO 2 On the Si wafer, after covering the sample with a mask, a Cr / Au electrode was deposited by a coating machine to construct a field effect transistor device, and a two-dimensional β-phase In 2 Se 3 Thin film field effect transistor, two-dimensional β′ phase In 2 Se 3 Thin-film field-effect transistors and two-dimensional α-phase In 2 Se 3 Thin film field effect transistor.

[0060] For the two-dimensional β′ phase In 2 Se 3 The transfer characteristics of thin film field effect transistors under different bias voltages were tested. The results are as follows Fig.13 As shown, Fig.13 For the two-dimensional β′ phase In 2 Se 3 Transfer characteristic hysteresis curve of thin film field effect transistor under different bias voltages, Fig.13 a is V ds =0.1V hysteresis curve, b is V ds =1V hysteresis curve, c is V ds =Hysteresis curve at 2V.

[0061] For two-dimensional α-phase In 2 Se 3 The transfer characteristics of thin film field effect transistors were tested under different gate voltage scanning intervals. The results are as follows Fig.14 As shown, Fig.14Two-dimensional α-phase In 2 Se 3 Transfer characteristic hysteresis curve of thin film field effect transistor in different gate voltage scanning ranges, Fig.14 In the figure, a is the hysteresis curve when the sweep range is ±20V, b is the hysteresis curve when the sweep range is ±40V, and c is the hysteresis curve when the sweep range is ±60V.

[0062] Depend on Fig.13 It can be seen that the current switching ratio is greater than 1×10 5 , the electron mobility is greater than 28 cm 2 V -1 s -1 , and there is an obvious hysteresis effect between the forward and reverse sweep curves, which is due to the β′ phase In 2 Se 3 It has a hysteresis effect caused by ferroelectric polarization, and the hysteresis window is greater than 20 V. It can be seen from this that the prepared two-dimensional β′ phase In 2 Se 3 Thin film field effect transistors have high performance and potential as memory devices.

[0063] Depend on Fig.14 It can be seen that the current switching ratio is greater than 1×10 3 , the electron mobility is greater than 50 cm 2 V -1 s -1 There are ferroelectric hysteresis windows in different gate voltage scanning intervals. 2 Se 3 Thin film field effect transistors have high electronic control performance and have the potential to be used as memory storage devices.

[0064] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a two-dimensional indium selenide crystal material, It is characterized in that include: In 2 O 3 Chemical vapor deposition was carried out with selenium as target to obtain pure β-phase two-dimensional indium selenide crystal material.

2. The preparation method according to claim 1, It is characterized in that include: In 2 O 3 With selenium as the target material, chemical vapor deposition was carried out to obtain pure β-phase two-dimensional In 2 Se 3 Crystalline material.

3. The preparation method according to claim 1, It is characterized in that During chemical vapor deposition, the In 2 O 3 The vertical distance between the target and the substrate is 1 mm~3 mm.

4. The preparation method according to claim 1, It is characterized in that The temperature of the selenium target during chemical vapor deposition is 250° C. to 300° C.; In 2 O 3 The temperature of the target material during chemical vapor deposition is 600℃~760℃.

5. The preparation method according to claim 1, It is characterized in that The chemical vapor deposition is performed in a reducing gas atmosphere; the flow rate of the reducing gas is 30 sccm-100 sccm.

6. The preparation method according to claim 5, It is characterized in that The reducing gas is H 2 and N 2 of mixed gases.

7. The preparation method according to any one of claims 1 to 6, It is characterized in that The chemical vapor deposition is carried out in a horizontal tube furnace in a reducing gas atmosphere, wherein the horizontal tube furnace is divided into an upstream temperature zone and a downstream temperature zone, wherein the reducing gas flows from the upstream temperature zone to the downstream temperature zone, wherein the selenium single target is located in the upstream temperature zone, and wherein the In 2 O 3 The target and substrate are located in the downstream temperature zone.

8. A two-dimensional indium selenide crystal material prepared according to the preparation method described in any one of claims 1 to 7.

9. A field effect transistor, It is characterized in that It includes a two-dimensional indium selenide crystal material prepared by the preparation method described in any one of claims 1 to 7.

10. The field effect transistor according to claim 9, It is characterized in that It includes: The surface is SiO 2 Si wafer; A two-dimensional indium selenide crystal material film prepared by the preparation method according to any one of claims 1 to 7; Cr / Au electrode.

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