A ternary layered selenide Ge3Sb4Se7 semiconductor material and its preparation method

Abstract

This invention relates to the field of crystal material preparation technology, specifically to a ternary layered selenide Ge3Sb4Se7 semiconductor material and its preparation method. The preparation method of the ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps: S001. Using germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 as raw materials, the temperature is raised to 900–950°C under vacuum conditions and held at this temperature for 12–24 hours; S002. After the holding period, the temperature is lowered to 475–500°C at a cooling rate of 1–5°C / min and held at this temperature for 3–5 days; After the holding period, the material is cooled to room temperature by furnace cooling or quenching to obtain a layered ternary selenide single-phase material with the chemical formula Ge3Sb4Se7. The ternary layered selenide Ge3Sb4Se7 semiconductor material obtained by this invention is a single-phase material with low thermal conductivity and low resistivity, thus showing potential applications in thermoelectric devices, photoelectric detection, and other fields.

Description

Technical Field

[0001] This invention relates to the field of crystal material preparation technology, specifically to a ternary layered selenide Ge3Sb4Se7 semiconductor material and its preparation method. Background Technology

[0002] Layered chalcogenides are formed by stacking two-dimensional or quasi-two-dimensional layered building blocks along a single direction. These building blocks are connected within their planes by stable ionic / covalent bonds, and van der Waals interactions exist between the layers. These materials possess ample tunable space in terms of chemical composition and phase structure, exhibiting rich physical and chemical properties, and show great potential for applications in fields such as field-effect transistors, photodetectors, gas sensors, spintronics, and thermoelectric devices.

[0003] Selenide Ge3Sb4Se7 is one of the first compounds discovered in the Ge-Sb-Se ternary system (Inorganic Chemistry, 2020, 59(16), 11207-11212). This compound is composed of alternating stacked Sb2Se2 and Ge3Sb2Se5 structural units, exhibiting an orthorhombic structure. Fmm 2) In this process, the Sb cations form an Sb-Sb chain structure within the Sb₂Se₂ layer. This selenide exhibits a layered structure similar to black phosphorus and SnSe, making it an indirect bandgap semiconductor material. Due to its low thermal conductivity and low resistivity, it holds promise for applications in thermoelectric devices, photoelectric detection, and other fields. However, in the currently disclosed Ge₃Sb₄Se₇ preparation process, other phases (such as GeSb₂Se₇) are prone to appear in the resulting product. 3、 The difficulty in obtaining single-phase and single-crystal materials of this compound (Sb2Se3) limits further research into its intrinsic properties and potential applications. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a ternary layered selenide Ge3Sb4Se7 semiconductor material and its preparation method, aiming to solve the technical problem that it is difficult to obtain single-phase and single-crystal materials of the compound Ge3Sb4Se7 in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of this invention provides a method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material, comprising the following steps:

[0007] S001. Using germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 as raw materials, the mixture is heated to 900-950℃ under vacuum conditions and kept at that temperature for 12-24 hours.

[0008] S002. After the heat preservation is completed, the temperature is reduced to 475-500℃ at a cooling rate of 1-5℃ / min, and held at this temperature for 3-5 days. After the heat preservation is completed, the material is cooled to room temperature by furnace cooling or quenching to obtain a layered ternary selenide single-phase material with the chemical formula Ge3Sb4Se7.

[0009] The method for preparing the ternary layered selenide Ge3Sb4Se7 semiconductor material, wherein in step S001, the purity of germanium powder, antimony powder, and selenium powder is ≥99.99%.

[0010] The method for preparing the ternary layered selenide Ge3Sb4Se7 semiconductor material, wherein in step S001, the vacuum degree of the vacuum condition is ≤1 Pa.

[0011] The method for preparing the ternary layered selenide Ge3Sb4Se7 semiconductor material, wherein in step S001, the heating rate is 1-5℃ / min.

[0012] A second aspect of this invention provides a ternary layered selenide Ge3Sb4Se7 semiconductor material, prepared by the method described above, wherein the single-wafer layer growth direction of the ternary layered selenide Ge3Sb4Se7 semiconductor material is crystallographically aligned. c Axial orientation.

[0013] Beneficial effects: This invention provides a method for preparing ternary layered selenide Ge3Sb4Se7 semiconductor material. By optimizing the high-temperature sintering temperature and the cooling and holding temperature, the method solves the problem that Ge3Sb4Se7 single-phase material cannot be obtained in the prior art, and provides support for the study of the physical properties of such materials and the development of functional devices. Attached Figure Description

[0014] Figure 1 This is an optical photograph of the Ge3Sb4Se7 material in Example 1.

[0015] Figure 2 The image shows the powder X-ray diffraction pattern of the Ge3Sb4Se7 material in Example 1.

[0016] Figure 3 The image shows a scanning electron microscope (SEM) image of the microstructure of the Ge3Sb4Se7 material in Example 1.

[0017] Figure 4 The image shows the X-ray energy spectrum of the Ge3Sb4Se7 material in Example 1.

[0018] Figure 5This is an atomic resolution structural diagram of the Ge3Sb4Se7 material [00l] in Example 1, projected along the direction.

[0019] Figure 6 This is an optical photograph of the Ge3Sb4Se7 single crystal material in Example 1.

[0020] Figure 7 The image shows the X-ray diffraction pattern of the Ge3Sb4Se7 single crystal material in Example 1.

[0021] Figure 8 This is an optical photograph of the material prepared in Comparative Example 1.

[0022] Figure 9 The image shows the powder X-ray diffraction pattern of the material prepared in Comparative Example 1.

[0023] Figure 10 The image shows the powder X-ray diffraction pattern of the material prepared in Comparative Example 3. Detailed Implementation

[0024] This invention provides a ternary layered selenide Ge3Sb4Se7 semiconductor material and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0025] This invention provides a method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material, comprising the following steps:

[0026] S001. Using germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 as raw materials, the mixture is heated to 900-950℃ under vacuum conditions and held at this temperature for 12-24 hours. Within this temperature range, the germanium powder, antimony powder, and selenium powder can be fully melted and reacted, thereby avoiding the formation of impurities.

[0027] S002. After the heat treatment is completed, the temperature is lowered to 475–500℃ at a rate of 1–5℃ / min, and held at this temperature for 3–5 days. After the heat treatment is completed, the material is cooled to room temperature by furnace cooling or quenching to obtain a layered ternary selenide single-phase material with the chemical formula Ge3Sb4Se7. Selecting a suitable cooling rate and conducting heat treatment within the temperature range of 475–500℃ can promote the homogenization of the chemical composition and microstructure of the Ge3Sb4Se7 material.

[0028] Preferably, in step S001, the purity of germanium powder, antimony powder, and selenium powder is ≥99.99%.

[0029] Preferably, in step S001, the vacuum level of the vacuum condition is ≤1 Pa to avoid the influence of air.

[0030] Preferably, in step S001, the heating rate is 1–5 °C / min. In step S001, the heating rate should not be too fast, otherwise the prepared material is prone to component segregation and low density.

[0031] Example 1

[0032] A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps:

[0033] Step 1: Ingredient Preparation and Packaging

[0034] Using germanium powder with a purity of 99.99%, antimony powder with a purity of 99.99%, and selenium powder with a purity of 99.99% as raw materials, the germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 were weighed and mixed and placed in a quartz tube. The vacuum was drawn to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device.

[0035] Step 2: High-temperature melting and firing

[0036] The vacuum-sealed quartz tube was placed vertically in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple. The quartz tube was heated from room temperature to 950°C at a rate of 5°C / min and held at that temperature for 12 hours.

[0037] Step 3: Material Annealing

[0038] For the material after the heat treatment in step two, the temperature was reduced from 950°C to 475°C at a cooling rate of 2.5°C / min, and held at this temperature for 3 days; the vacuum-sealed quartz tube was cooled to room temperature with the furnace, and then the material was removed from the quartz tube.

[0039] Material microstructure and structural analysis

[0040] The morphology, chemical composition, and structure of the prepared materials were analyzed and characterized using optical microscopy, X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and transmission electron microscopy. Specific characterization results are as follows: Figures 1 to 5 As shown. Analysis of powder X-ray diffraction patterns (...) Figure 2 The results of comparison with standard cards were analyzed, and the microstructure of the material was obtained by comprehensive analysis of scanning electron microscopy and X-ray energy dispersive spectroscopy. Figure 3 ), atomic ratio of each element ( Figure 4 ), and its crystal structure was obtained using a high-angle annular dark-field image obtained by transmission electron microscopy (TEM). Figure 5 The material obtained under these conditions was determined to be a single-phase material with a chemical composition of Ge3Sb4Se7.

[0041] In addition, observation of the millimeter-sized needle-like material obtained from the reaction confirmed that the macroscopic structure of the material has a layered morphological characteristic. Figure 6 ), using X-ray testing and indexing of its diffraction patterns ( Figure 7 The diffraction peaks were determined to be of the Ge3Sb4Se7 crystal structure (00). l The crystal planes, whose lamellar growth directions are crystallographically defined. c The axial orientation indicates it is a Ge3Sb4Se7 single crystal.

[0042] Example 2

[0043] A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps:

[0044] Step 1: Ingredient Preparation and Packaging

[0045] Using germanium powder with a purity of 99.99%, antimony powder with a purity of 99.99%, and selenium powder with a purity of 99.99% as raw materials, the germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 were weighed and mixed and placed in a quartz tube. The vacuum was drawn to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device.

[0046] Step 2: High-temperature melting and firing

[0047] The vacuum-sealed quartz tube was placed vertically in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple. The quartz tube was heated from room temperature to 950°C at a rate of 5°C / min and held at that temperature for 12 hours.

[0048] Step 3: Material Quenching Treatment

[0049] For the material after heat preservation and firing in step two, the temperature was reduced from 950°C to 475°C at a cooling rate of 2.5°C / min, and held at this temperature for 3 days; the vacuum-sealed quartz tube was quenched and cooled to room temperature, and then the material was taken out of the quartz tube.

[0050] Material microstructure and structural analysis

[0051] The morphology, chemical composition, and structure of the prepared material were analyzed and characterized by optical microscopy, X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and transmission electron microscopy, confirming that a Ge3Sb4Se7 material with a distinct layered structure was obtained.

[0052] Example 3

[0053] A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps:

[0054] Step 1: Ingredient Preparation and Packaging

[0055] Using germanium powder with a purity of 99.99%, antimony powder with a purity of 99.99%, and selenium powder with a purity of 99.99% as raw materials, the germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 were weighed and mixed and placed in a quartz tube. The vacuum was drawn to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device.

[0056] Step 2: High-temperature melting and firing

[0057] The vacuum-sealed quartz tube was placed vertically in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple. The quartz tube was heated from room temperature to 950°C at a rate of 5°C / min and held at that temperature for 12 hours.

[0058] Step 3: Material Annealing

[0059] For the material after heat preservation and firing in step two, the temperature was reduced from 950°C to 500°C at a cooling rate of 2.5°C / min, and held at this temperature for 3 days; the vacuum-sealed quartz tube was cooled to room temperature with the furnace, and then the material was removed from the quartz tube.

[0060] Material microstructure and structural analysis

[0061] The morphology, chemical composition, and structure of the prepared material were analyzed and characterized by optical microscopy, X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and transmission electron microscopy, confirming that a Ge3Sb4Se7 material with a distinct layered structure was obtained.

[0062] Example 4

[0063] A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps:

[0064] Step 1: Ingredient Preparation and Packaging

[0065] Using germanium powder with a purity of 99.99%, antimony powder with a purity of 99.99%, and selenium powder with a purity of 99.99% as raw materials, the germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 were weighed and mixed and placed in a quartz tube. The vacuum was drawn to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device.

[0066] Step 2: High-temperature melting and firing

[0067] The vacuum-sealed quartz tube was placed vertically in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple. The quartz tube was heated from room temperature to 900°C at a rate of 5°C / min and held at that temperature for 12 hours.

[0068] Step 3: Material Annealing

[0069] For the material after heat preservation and firing in step two, the temperature was reduced from 900℃ to 500℃ at a cooling rate of 2.5℃ / min, and held at this temperature for 5 days; the vacuum-sealed quartz tube was cooled to room temperature with the furnace, and then the material was taken out of the quartz tube.

[0070] Material microstructure and structural analysis

[0071] The morphology, chemical composition, and structure of the prepared material were analyzed and characterized by optical microscopy, X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and transmission electron microscopy, confirming that a Ge3Sb4Se7 material with a distinct layered structure was obtained.

[0072] Comparative Example 1

[0073] A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps:

[0074] Step 1: Ingredient Preparation and Packaging

[0075] Using germanium powder with a purity of 99.99%, antimony powder with a purity of 99.99%, and selenium powder with a purity of 99.99% as raw materials, the germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 were weighed and mixed and placed in a quartz tube. The vacuum was drawn to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device.

[0076] Step 2: High-temperature firing

[0077] The vacuum-sealed quartz tube was placed vertically in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple. The quartz tube was heated from room temperature to 475°C at a rate of 5°C / min and held at that temperature for 3 days.

[0078] Step 3: Material Quenching Treatment

[0079] After heat preservation and firing, the vacuum-sealed quartz tube is directly quenched, and then the material is taken out from the quartz tube.

[0080] Material microstructure and structural analysis

[0081] The morphology, chemical composition, and structure of the prepared materials were analyzed and characterized using optical microscopy, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectroscopy. Figure 8 Optical photographs of the prepared material revealed that no dense product was formed under these process conditions, indicating that the raw materials could not react sufficiently; while the powder X-ray diffraction pattern ( Figure 9 The results indicate that the obtained material includes the Ge3Sb4Se7 phase and other phases such as Sb2Se3 (significant characteristic diffraction peaks are indicated by arrows). The combined results show that no single-phase Ge3Sb4Se7 material was obtained.

[0082] Comparative Example 2

[0083] A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps:

[0084] Step 1: Ingredient Preparation and Packaging

[0085] Using germanium powder with a purity of 99.99%, antimony powder with a purity of 99.99%, and selenium powder with a purity of 99.99% as raw materials, the germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 were weighed and mixed and placed in a quartz tube. The vacuum was drawn to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device.

[0086] Step 2: High-temperature firing

[0087] The vacuum-sealed quartz tube is placed vertically in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple. The quartz tube is heated from room temperature to 475°C at a rate of 5°C / min and held at this temperature for 3 days. After the holding and firing process, the vacuum-sealed quartz tube is cooled to room temperature with the furnace, and then the material is removed from the quartz tube.

[0088] Material microstructure and structural analysis

[0089] The morphology, chemical composition, and structure of the prepared materials were analyzed and characterized by optical microscopy, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectroscopy. The materials prepared under these process conditions were consistent with those of Comparative Example 1. The materials obtained included Ge3Sb4Se7 phase and other phases such as Sb2Se3, but no single-phase Ge3Sb4Se7 material was obtained.

[0090] Comparative Example 3

[0091] A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material includes the following steps:

[0092] Step 1: Ingredient Preparation and Packaging

[0093] Using germanium powder with a purity of 99.99%, antimony powder with a purity of 99.99%, and selenium powder with a purity of 99.99% as raw materials, the germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 were weighed and mixed and placed in a quartz tube. The vacuum was drawn to ≤1 Pa, and then the quartz tube containing the sample was sealed using a flame sealing device.

[0094] Step 2: High-temperature firing

[0095] The vacuum-sealed quartz tube is placed vertically in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple. The quartz tube is heated from room temperature to 600°C at a rate of 5°C / min and held at this temperature for 3 days. After the holding and firing process, the vacuum-sealed quartz tube is cooled to room temperature with the furnace, and then the material is removed from the quartz tube.

[0096] Material microstructure and structural analysis

[0097] The morphology, chemical composition, and structure of the prepared material were analyzed and characterized using optical microscopy, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectroscopy. The material prepared under these process conditions was similar to that of Comparative Example 1, but the intensity of the impurity characteristic peaks was reduced. Figure 10 Ge3Sb4Se7 single-phase material has not yet been obtained.

[0098] In summary, the results of the above examples and comparative examples show that only within a specific firing temperature range and under specific cooling and holding processes can the obtained material be guaranteed to be a single-phase material.

[0099] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a ternary layered selenide Ge3Sb4Se7 semiconductor material, characterized in that, Includes the following steps: S001. Using germanium powder, antimony powder, and selenium powder in a molar ratio of 3:4:7 as raw materials, the mixture is heated to 900-950℃ under vacuum conditions and kept at that temperature for 12-24 hours. S002. After the heat preservation is completed, the temperature is reduced to 475-500℃ at a cooling rate of 1-5℃ / min, and held at this temperature for 3-5 days. After the heat preservation is completed, the material is cooled to room temperature by furnace cooling or quenching to obtain a layered ternary selenide single-phase material with the chemical formula Ge3Sb4Se7.

2. The method for preparing the ternary layered selenide Ge3Sb4Se7 semiconductor material according to claim 1, characterized in that, In step S001, the purity of germanium powder, antimony powder, and selenium powder is ≥99.99%.

3. The method for preparing the ternary layered selenide Ge3Sb4Se7 semiconductor material according to claim 1, characterized in that, In step S001, the vacuum degree of the vacuum condition is ≤1 Pa.

4. The method for preparing the ternary layered selenide Ge3Sb4Se7 semiconductor material according to claim 1, characterized in that, In step S001, the heating rate is 1–5 °C / min.

5. A ternary layered selenide Ge3Sb4Se7 semiconductor material, characterized in that, The ternary layered selenide Ge3Sb4Se7 semiconductor material is prepared by the method described in any one of claims 1-4, wherein the single-wafer layer growth direction of the ternary layered selenide Ge3Sb4Se7 semiconductor material is crystallographically... c Axial orientation.

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