Tellurium-doped selenide semiconductor material and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor materials, in particular to a tellurium-doped selenide semiconductor material and a preparation method thereof. The chemical formula of the tellurium-doped selenide semiconductor material is FeIn2Se4-xTex, x is more than 0 and less than or equal to 1.5, and the crystal structure is a rhombohedral phase (R-3m). Compared with FeIn2Se4, the tellurium-doped selenide semiconductor material provided by the invention has the advantages that the band gap is changed, the conductivity in the temperature range of 600-750 K is obviously reduced, different semiconductor properties can be provided, and the variety of FeIn2Se4-based materials is enriched.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a tellurium-doped selenide semiconductor material and a preparation method thereof. Background Art

[0002] AB2X4 ternary compound (where A=Fe, Mn, Ni, Co; B=Ga, In; X=S, Se, Te) contains d Transition metal elements with insufficient shell electron filling have novel physical properties that combine semiconductors and magnetism, making them materials with broad application prospects in solar cells, optical modulators, photodetectors, spin electronics and other functional devices controlled by magnetic fields.

[0003] The layered ternary selenide FeIn2Se4 has a ZnIn2S4 type structure (space group: R -3 m ), a non-magnetic semiconductor material at room temperature. In order to directly change and optimize the functional parameters of this ternary selenide, it is necessary to synthesize and study different types of alternative solid solutions based on this material. In the FeIn2S4–FeIn2Se4 material system, the use of sulfur to replace selenium can regulate the physical properties of FeIn2Se4, but sulfur doping makes the crystal structure of the generated material not only related to temperature, but also to the doping amount of sulfur. Among them, FeIn2SSe3 has an α-FeGa2S4 type structure, while FeIn2S2Se2 has a MgAl2S4 type structure. It is difficult to obtain FeIn2(S4) with a single-phase structure. 1-x Se x )4 materials, thereby affecting the regulation of material properties (Journal of Alloys and Compounds 270 (1998) 83-87. Journal of Solid State Chemistry 164, 326-331 (2002).). In the FeGa2Se4-FeIn2Se4 system, the experimentally obtained FeGaInSe4 has a space group of R- 3 m , which is different from the FeIn2Se4 structure, and the performance of FeGaInSe4 materials has not been reported (Journal of Phase Equilibria and Diffusion (2019) 40:787–796.). 1-x Fe x In2Se4 (0≤x≤1) system, the material structure changes complexly with the Mn doping amount, and there are R -3 m , P 3m 1 and P 63 mc Several space group structures exist, and only Mn 0.1 Fe 0.9 The energy gap of In2Se4 (1.06 eV at 300 K and 1.14 eV at 10 K) varies slightly with temperature (Crystal Research Technology 40, No. 10-11, 1064-1066 (2005).). Currently reported FeIn2Se4-based material systems still suffer from limitations such as the insignificant effect of element doping on material properties (such as the band gap) and structural changes caused by element doping, hindering the development of FeIn2Se4-based materials with controllable and stable properties. Therefore, identifying new FeIn2Se4-based materials and further enriching the variety of such materials is crucial for promoting their application in related technologies. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a tellurium-doped selenide semiconductor material and a preparation method thereof, aiming to enrich the types of FeIn2Se4-based materials and provide more options for the development of functional devices.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention provides a tellurium-doped selenide semiconductor material having the chemical formula FeIn2Se 4-x Te x , where 0<x≤1.5, the crystal structure is rhombohedral phase ( R -3 m ).

[0006] The second aspect of the present invention provides a method for preparing a semiconductor material, which is used to prepare the tellurium-doped selenide semiconductor material as described above, comprising the following steps: using iron powder, indium powder, selenium powder, and tellurium powder in a molar ratio of 1:2:(4-x):x as raw materials, melting and sintering at high temperature under vacuum conditions, and quenching to obtain the chemical formula FeIn2Se 4-x Te x Tellurium-doped selenide semiconductor materials.

[0007] The method for preparing the semiconductor material comprises the following steps: S1. High-temperature melt sintering: Using iron powder, indium powder, selenium powder, and tellurium powder in a molar ratio of 1:2:(4-x):x as raw materials, with the purity of the raw materials being ≥99.99%, the temperature is raised to 950-1100°C under vacuum conditions and maintained at this temperature for 12-24 hours; S2. Quenching treatment: After the heat preservation is completed, the temperature is lowered to 700-750℃ and kept at this temperature for 72-96 hours; after the heat preservation is completed, the quenching is cooled to room temperature to obtain the chemical formula FeIn2Se 4-x Te x Tellurium-doped selenide semiconductor materials.

[0008] The method for preparing the semiconductor material further comprises the following steps: S3. Using mechanical exfoliation method, FeIn2Se with thin layer structure was obtained from the tellurium-doped selenide semiconductor material prepared in S2. 4-x Te x Material.

[0009] The method for preparing the semiconductor material, wherein, during the high-temperature melting and firing, the vacuum degree under vacuum conditions is ≤1Pa.

[0010] The method for preparing the semiconductor material, wherein, during the high-temperature melting and firing and the cooling and heat preservation, the heating and cooling rate is 2-5°C / min.

[0011] Beneficial effect: The present invention provides a tellurium-doped selenide semiconductor material, the chemical formula of the tellurium-doped selenide semiconductor material is FeIn2Se 4-x Te x , 0<x≤1.5. The tellurium-doped selenides disclosed in this invention exhibit significantly different electrical properties (such as band gap) compared to undoped tellurium selenides, further enriching the variety of such materials. Furthermore, this invention discloses methods for preparing these tellurium-doped selenides and clarifies the effects of different preparation processes on their performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FeIn2Se in Example 1 2.5 Te 1.5 Optical photograph of the material.

[0013] Figure 2 FeIn2Se in Example 1 2.5 Te 1.5 X-ray powder diffraction pattern of the material.

[0014] Figure 3 FeIn2Se in Example 1 2.5 Te 1.5 Scanning electron microscope image of the cross-section microstructure of the material.

[0015] Figure 4 FeIn2Se in Example 1 2.5 Te 1.5 X-ray energy spectrum analysis of materials.

[0016] Figure 5 FeIn2Se in Example 1 2.5 Te 1.5 Atomic resolution structure of the material in the [1-100] projection direction.

[0017] Figure 6 FeIn2Se in Example 1 2.5 Te 1.5 A graph showing the temperature variation of a material's electrical conductivity and its Arrhenius plot.

[0018] Figure 7 FeIn2Se in Example 1 2.5 Te 1.5 Thin nanosheets or few-layer two-dimensional FeIn2Se 2.5 Te 1.5 Optical photograph of the material.

[0019] Figure 8 FeIn2Se in Example 1 2.5 Te 1.5 X-ray diffraction patterns of thin nanosheets.

[0020] Figure 9 This is the X-ray powder diffraction pattern of the FeIn2Se3Te material in Example 2.

[0021] Figure 10 The conductivity of the FeIn2Se3Te material in Example 2 changes with temperature and its Arrhenius spectrum.

[0022] Figure 11 FeIn2Se in Example 3 3.5 Te 0.5 X-ray powder diffraction pattern of the material.

[0023] Figure 12 FeIn2Se in Example 3 3.5 Te 0.5 A graph showing the temperature variation of a material's electrical conductivity and its Arrhenius plot.

[0024] Figure 13 This is the X-ray powder diffraction pattern of the FeIn2Se4 material in Comparative Example 1.

[0025] Figure 14 The conductivity of the FeIn2Se4 material in Comparative Example 1 changes with temperature and its Arrhenius spectrum.

[0026] Figure 15FeIn2Se under different preparation processes in Comparative Examples 2-3 2.5 Te 1.5 X-ray powder diffraction pattern of the material.

[0027] Figure 16 This is the X-ray powder diffraction pattern of the FeIn2Se2Te2 material in Comparative Example 4. DETAILED DESCRIPTION

[0028] The present invention provides a tellurium-doped selenide semiconductor material and a method for preparing the same. To further clarify the objectives, technical solutions, and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended only to illustrate the present invention and are not intended to limit the present invention.

[0029] Example 1 A tellurium-doped selenide semiconductor material, the preparation method of which comprises the following steps: A01. Ingredients and packaging Using 99.99% pure iron powder, 99.99% pure indium powder, 99.99% pure selenium powder, and 99.99% pure tellurium powder as raw materials, the chemical formula FeIn2Se 2.5 Te 1.5 Tellurium-doped selenide semiconductor material; iron powder, indium powder, selenium powder, and tellurium powder are weighed and configured in a molar ratio of 1:2:2.5:1.5, mixed and placed in a quartz tube, evacuated to ≤1 Pa, and then sealed with a flame sealing device; A02. High temperature melting and firing Place the vacuum-sealed quartz tube vertically in a single-temperature-zone pit furnace, with the quartz tube close to the thermocouple, and heat it from room temperature to 950°C at a heating rate of 5°C / min, and keep it at this temperature for 12 h. A03. Material quenching treatment After the firing and holding process, the temperature was lowered from 950°C to 750°C at a rate of 2.5°C / min and kept at 750°C for 72 hours. The vacuum-sealed quartz tube was quenched and the material was then removed from the tube for organization, structure, and performance analysis.

[0030] Figure 1 This is an optical microscope photo. Figure 2 is the X-ray diffractometer result, Figure 3 The results of scanning electron microscopy are shown in Figure 2. Figure 4 is the X-ray energy spectrum, Figure 5 Transmission electron microscopy results.

[0031] According to the FeIn2Se4 structural model (Journal of Phase Equilibria and Diffusion (2019)40:787–796.), and by analyzing the X-ray energy spectrum ( Figure 4 ) and X-ray diffraction spectra ( Figure 2 ), determine the FeIn2Se obtained under the conditions of Example 1 2.5 Te 1.5 The material is a single-phase material; in addition, the high-angle annular dark field image ( Figure 5 ), further indicating that the crystal structure of the obtained material is consistent with the FeIn2Se4 structural model, with a layered structure along the c-axis. Scanning electron microscopy shows that the macrostructure of this material has a layered morphology ( Figure 3 ). In terms of performance, FeIn2Se 2.5 Te 1.5 The electrical conductivity of the material increases with temperature, and increases significantly above 600K. 2.5 Te 1.5 The conductivity of the material changes with temperature and its Arrhenius spectrum, and its band gap is measured to be 1.3eV ( Figure 6 ).

[0032] Figure 3 As shown in the figure, the prepared material has a layered morphology, and further through the mechanical exfoliation method, FeIn2Se with thin layer nanosheets or few layers of two-dimensional 2.5 Te 1.5 Materials (such as Figure 7 ), by indexing its X-ray diffraction pattern ( Figure 8 ), determine the diffraction peak corresponding to (000 l )( l = 2, 3, 4…) crystal planes. The above results indicate that the obtained thin layer material is a single crystal and the thickness direction of the sheet is oriented along the crystallographic c-axis of its structure.

[0033] Example 2 A tellurium-doped selenide semiconductor material, the preparation method of which comprises the following steps: A01. Ingredients and packaging Using 99.99% pure iron powder, 99.99% pure indium powder, 99.99% pure selenium powder, and 99.99% pure tellurium powder as raw materials, a tellurium-doped selenide semiconductor material with the chemical formula FeIn2Se3Te was prepared. The iron powder, indium powder, selenium powder, and tellurium powder were weighed and prepared in a molar ratio of 1:2:3:1. The mixture was placed in a quartz tube, evacuated to ≤1 Pa, and then sealed using a flame sealing device. A02. High temperature melting and firing Place the vacuum-sealed quartz tube vertically in a single-temperature-zone pit furnace, with the quartz tube close to the thermocouple, and heat it from room temperature to 1100°C at a heating rate of 5°C / min, and keep it at this temperature for 12 h. A03. Material quenching treatment After the firing and holding process, the temperature was lowered from 1100°C to 750°C at a rate of 2.5°C / min and kept at 750°C for 96 hours. The vacuum-sealed quartz tube was quenched and the material was then removed from the tube for organization, structure, and performance analysis.

[0034] The analysis and characterization results of optical microscopy, X-ray diffractometer, scanning electron microscope and X-ray energy spectrometer were similar to those of Example 1. The X-ray powder diffraction pattern of the prepared material did not show any characteristic diffraction peaks of other phases ( Figure 9 At the same time, combined with scanning electron microscopy and X-ray energy spectrum analysis, it was determined that the obtained material is a single-phase material, and the crystal structure of the material is the same as that of FeIn2Se4. Based on the conductivity variation spectrum of FeIn2Se3Te material with temperature and its Arrhenius spectrum, its band gap was measured to be 1.22 eV ( Figure 10 ).

[0035] Example 3 A tellurium-doped selenide semiconductor material, the preparation method of which comprises the following steps: A01. Ingredients and packaging Using 99.99% pure iron powder, 99.99% pure indium powder, 99.99% pure selenium powder, and 99.99% pure tellurium powder as raw materials, the chemical formula FeIn2Se 3.5 Te 0.5 Tellurium-doped selenide semiconductor material; iron powder, indium powder, selenium powder, and tellurium powder are weighed and configured in a molar ratio of 1:2:3.5:0.5, mixed and placed in a quartz tube, evacuated to ≤1 Pa, and then sealed with a flame sealing device; A02. High temperature melting and firing Place the vacuum-sealed quartz tube vertically in a single-temperature-zone pit furnace, with the quartz tube close to the thermocouple, and heat it from room temperature to 950°C at a heating rate of 5°C / min, and keep it at this temperature for 24 h. A03. Material quenching treatment After the firing and holding process, the temperature was lowered from 950°C to 700°C at a rate of 2.5°C / min and kept at 700°C for 96 hours. The vacuum-sealed quartz tube was quenched and the material was then removed from the tube for organization, structure, and performance analysis.

[0036] The analysis and characterization results of optical microscopy, X-ray diffractometer, scanning electron microscope and X-ray energy spectrometer were similar to those of Example 1. The X-ray powder diffraction pattern of the prepared material did not show any characteristic diffraction peaks of other phases ( Figure 11 At the same time, combined with scanning electron microscopy and X-ray energy spectrum analysis, it was determined that the obtained material was a single-phase material, and the crystal structure of the material was the same as that of FeIn2Se4. 3.5 Te 0.5 The conductivity of the material changes with temperature and its Arrhenius spectrum, and its band gap is measured to be 1.14eV ( Figure 12 ).

[0037] Comparative Example 1 A selenide semiconductor material, the preparation method of which comprises the following steps: A01. Ingredients and packaging Using 99.99% pure iron powder, 99.99% pure indium powder, and 99.99% pure selenium powder as raw materials, a tellurium-doped selenide semiconductor material with the chemical formula FeIn2Se4 was prepared. The iron powder, indium powder, and selenium powder were weighed and prepared in a molar ratio of 1:2:4, mixed and placed in a quartz tube, and vacuumed to ≤1 Pa. The quartz tube containing the sample was then sealed using a flame sealing device. A02. High temperature melting and firing Place the vacuum-sealed quartz tube vertically in a single-temperature-zone pit furnace, with the quartz tube close to the thermocouple, and heat it from room temperature to 1100°C at a heating rate of 2°C / min, and keep it at this temperature for 24 h. A03. Material quenching treatment After the firing and holding process, the temperature was lowered from 1100°C to 700°C at a rate of 2.5°C / min and kept at 700°C for 72 hours. The vacuum-sealed quartz tube was quenched and the material was then removed from the tube for organization, structure, and performance analysis.

[0038] The analysis and characterization results of optical microscopy, X-ray diffractometer, scanning electron microscope and X-ray energy spectrometer were similar to those of Example 1. The X-ray powder diffraction pattern of the prepared material did not show any characteristic diffraction peaks of other phases ( Figure 13 At the same time, combined with scanning electron microscopy and X-ray energy spectrum analysis, it was determined that the obtained material was a single-phase FeIn2Se4 material. The electrical conductivity of the FeIn2Se4 material increases with temperature, with a significant increase above 550 K. Based on the temperature-dependent conductivity spectrum of the FeIn2Se4 material and its Arrhenius spectrum, its band gap was measured to be 0.87 eV ( Figure 14 ).

[0039] Comparative Example 2 A tellurium-doped selenide, the preparation method of which comprises the following steps: A01. Ingredients and packaging Using 99.99% pure iron powder, 99.99% pure indium powder, 99.99% pure selenium powder, and 99.99% pure tellurium powder as raw materials, the chemical formula FeIn2Se 2.5 Te 1.5 Tellurium-doped selenide semiconductor material; iron powder, indium powder, selenium powder, and tellurium powder are weighed and configured in a molar ratio of 1:2:2.5:1.5, mixed and placed in a quartz tube, evacuated to ≤1 Pa, and then sealed with a flame sealing device; A02. High temperature melting and firing Place the vacuum-sealed quartz tube vertically in a single-temperature-zone pit furnace, with the quartz tube close to the thermocouple, and heat it from room temperature to 950°C at a heating rate of 5°C / min, and keep it at this temperature for 12 hours; A03. Material quenching treatment After the firing and holding process, the temperature was lowered from 950°C to 800°C at a rate of 2.5°C / min and kept at 800°C for 72 hours. The vacuum-sealed quartz tube was quenched and the material was then removed from the tube for microstructure analysis.

[0040] The microstructure analysis by X-ray diffractometer confirmed that the material obtained under this condition included FeIn2Se4 structure and a small amount of InSe phase (characteristic diffraction peaks are shown by arrows), and no single-phase material was obtained ( Figure 15 ).

[0041] Comparative Example 3 A tellurium-doped selenide, the preparation method of which comprises the following steps: A01. Ingredients and packaging Using 99.99% pure iron powder, 99.99% pure indium powder, 99.99% pure selenium powder, and 99.99% pure tellurium powder as raw materials, the chemical formula FeIn2Se 2.5 Te 1.5 Tellurium-doped selenide semiconductor material; iron powder, indium powder, selenium powder, and tellurium powder are weighed and configured in a molar ratio of 1:2:2.5:1.5, mixed and placed in a quartz tube, evacuated to ≤1 Pa, and then sealed with a flame sealing device; A02. High temperature melting and firing Place the vacuum-sealed quartz tube vertically in a single-temperature-zone pit furnace, with the quartz tube close to the thermocouple, and heat it from room temperature to 950°C at a heating rate of 5°C / min, and keep it at this temperature for 12 hours; A03. Material quenching treatment After the firing and holding process, the temperature was lowered from 950°C to 650°C at a rate of 2.5°C / min and kept at 650°C for 72 hours. The vacuum-sealed quartz tube was quenched and the material was then removed from the tube for microstructure analysis.

[0042] The microstructure analysis by X-ray diffractometer confirmed that the material obtained under this condition included FeIn2Se4 structure and a small amount of InSe phase (characteristic diffraction peaks are shown by arrows), and no single-phase material was obtained ( Figure 15 ).

[0043] Comparative Example 4 A tellurium-doped selenide, the preparation method of which comprises the following steps: A01. Ingredients and packaging Using 99.99% pure iron powder, 99.99% pure indium powder, 99.99% pure selenium powder, and 99.99% pure tellurium powder as raw materials, the goal is to prepare a tellurium-doped selenide semiconductor material with the chemical formula FeIn2Se2Te2. The iron powder, indium powder, selenium powder, and tellurium powder were weighed and configured in a molar ratio of 1:2:2:2, mixed, and placed in a quartz tube. The mixture was evacuated to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device. A02. High temperature melting and firing Place the vacuum-sealed quartz tube vertically in a single-temperature-zone pit furnace, with the quartz tube close to the thermocouple, and heat it from room temperature to 950°C at a heating rate of 5°C / min, and keep it at this temperature for 24 hours; A03. Material quenching treatment After the firing and holding process, the temperature was lowered from 950°C to 700°C at a rate of 2.5°C / min and kept at 700°C for 72 hours. The vacuum-sealed quartz tube was quenched and the material was then removed from the tube for microstructure analysis.

[0044] The microstructure analysis by X-ray diffractometer confirmed that the material obtained under this condition included FeIn2Se4 structure and a small amount of InSe phase (characteristic diffraction peaks are shown by arrows), and no single-phase material was obtained ( Figure 16 ). From the results of Comparative Example 4, it can be seen that a single-phase material with a FeIn2Se4 structure can be obtained by accurately controlling the dosage ratio of iron powder, indium powder, selenium powder, and tellurium powder.

[0045] In summary, for FeIn2Se 4-x Te x (0<x≤1.5) material, through the preparation method and parameter control of the present invention, a single-phase material with FeIn2Se4 structure can be obtained. 4-x Te x(0<x≤1.5) and FeIn2Se 4. The electrical conductivity of the material changes with temperature, and it is clear that tellurium doping can significantly reduce the electrical conductivity of FeIn2Se4 material in the temperature range of 600-750K. 4-x Te x The conductivity of the material changes with temperature and its Arrhenius spectrum. It is measured that tellurium doping can change the band gap of FeIn2Se4. For example, compared with the band gap of FeIn2Se4 (0.87 eV), FeIn2Se 2.5 Te 1.5 The band gap at room temperature is 1.3eV. In addition, the present invention also discloses that FeIn2Se with thin nanosheets or few-layer two-dimensional can be obtained by using a mechanical exfoliation method. 4-x Te x (0<x≤1.5) single crystal materials (such as Figure 7 FeIn2Se shown 2.5 Te 1.5 nanosheets).

[0046] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A tellurium-doped selenide semiconductor material, characterized in that: The chemical formula is FeIn2Se 4-x Te x , where 0<x≤1.5, the crystal structure is rhombohedral phase ( R -3 m ).

2. A method for preparing a semiconductor material, for preparing the tellurium-doped selenide semiconductor material according to claim 1, characterized in that: The process comprises the following steps: using iron powder, indium powder, selenium powder and tellurium powder in a molar ratio of 1:2:(4-x):x as raw materials, melting and sintering at high temperature under vacuum conditions, and quenching treatment to obtain the chemical formula of FeIn2Se 4-x Te x Tellurium-doped selenide semiconductor materials.

3. The method for preparing a semiconductor material according to claim 2, wherein: The steps include: S1. High-temperature melt sintering: Using iron powder, indium powder, selenium powder, and tellurium powder in a molar ratio of 1:2:(4-x):x as raw materials, with the purity of the raw materials being ≥99.99%, the temperature is raised to 950-1100°C under vacuum conditions and maintained at this temperature for 12-24 hours; S2. Quenching treatment: After the heat preservation is completed, the temperature is lowered to 700-750℃ and kept at this temperature for 72-96 hours; after the heat preservation is completed, the quenching is cooled to room temperature to obtain the chemical formula FeIn2Se 4-x Te x Tellurium-doped selenide semiconductor materials.

4. The method for preparing a semiconductor material according to claim 3, wherein: The following steps are also included: S3. Using mechanical exfoliation method, FeIn2Se with thin layer structure was obtained from the tellurium-doped selenide semiconductor material prepared in S2. 4-x Te x Material.

5. The method for preparing a semiconductor material according to claim 3, wherein: During the high-temperature melting and firing, the vacuum degree under vacuum conditions is ≤1Pa.

6. The method for preparing a semiconductor material according to claim 3, wherein: During the high-temperature melting and firing and the cooling and heat preservation, the heating and cooling rate is 2-5°C / min.

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