Large-size ternary layered In2Ge2Se6 single crystal material and preparation method thereof

Abstract

The invention relates to the technical field of crystal material preparation, in particular to a large-size ternary layered In2Ge2Se6 single crystal material and a preparation method thereof. According to the preparation method, a chemical vapor transport method is adopted, iodine is taken as a transport agent, and the large-size ternary layered In2Ge2Se6 single crystal material is finally prepared by optimizing the concentration and treatment temperature of the iodine, so that a material support is provided for related physical property research and development and application of semiconductor photoelectric devices.

Description

Technical Field

[0001] This invention relates to the field of crystal material preparation technology, and in particular to a large-size ternary layered In2Ge2Se6 single crystal material and its preparation method. Background Technology

[0002] The ternary selenide In2Ge2Se6 is a rhombohedral phase with a layered structure (space group: R Semiconductor materials. Their band gap E g With a voltage of approximately 1.43 eV and low thermal conductivity, it has potential applications in semiconductor optoelectronic devices, solar cells, and thermoelectric devices. Currently, Chinese invention patent CN119637814B discloses "a layered ternary selenide, a layered ternary selenide single-phase material and its preparation method," specifically disclosing the synthesis of In2Ge2Se6 layered ternary selenide single-phase material through high-temperature melting, holding at a specific temperature range, and quenching processes. While the aforementioned invention patent directly obtained In2Ge2Se6 single-phase material and obtained millimeter-scale single crystals through mechanical exfoliation, it still suffers from technical problems such as the potential for the formation of other phases like In2Se3, the need for high-temperature quenching, and the relatively small size of the single crystals.

[0003] The objective of this invention is to further optimize growth conditions to prepare large-size, high-quality ternary layered In2Ge2Se6 single crystal materials, providing material support for related property studies and the development and application of semiconductor optoelectronic devices. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a large-size ternary layered In2Ge2Se6 single crystal material and its preparation method, aiming to solve the technical problem of small size of In2Ge2Se6 single-phase material in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this invention provides a method for preparing large-size ternary layered In2Ge2Se6 single crystal material, comprising the following steps: S001. Using indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 as raw materials, mix indium powder, germanium powder, and selenium powder in a quartz tube, and add 4-6 mg / mL of iodine particles to make the vacuum degree inside the quartz tube ≤1 Pa, and seal the quartz tube. S002. Place the end of the quartz tube with raw material in the high-temperature zone of the dual-temperature furnace, and the end without raw material in the low-temperature zone of the dual-temperature furnace; raise the temperature to 500±25℃ at the low-temperature zone end and 600±25℃ at the high-temperature zone end; after holding at this temperature range for 5 to 7 days, allow the vacuum-sealed quartz tube to cool naturally to room temperature; clean and dry the grown material to obtain a large-size ternary layered In2Ge2Se6 single crystal material.

[0006] The method for preparing large-size ternary layered In2Ge2Se6 single crystal material, wherein the purity of the indium powder, germanium powder, and selenium powder is ≥99.99wt%.

[0007] The method for preparing large-size ternary layered In2Ge2Se6 single crystal material, wherein the heating time in SO02 is 120-600 min.

[0008] The method for preparing large-size ternary layered In2Ge2Se6 single crystal material, wherein in step S002, the grown material is placed in alcohol for cleaning and drying.

[0009] The second aspect of the present invention provides a large-size ternary layered In2Ge2Se6 single crystal material, which is prepared by the preparation method of the large-size ternary layered In2Ge2Se6 single crystal material as described above.

[0010] Beneficial effects: This invention provides a method for preparing large-size ternary layered In2Ge2Se6 single crystal materials. The preparation method optimizes the crystal growth environment, allowing the crystal to grow in a dual-temperature zone environment, and uses iodine as a transport agent to finally obtain large-size ternary layered In2Ge2Se6 single crystal materials, solving the technical problem that other phases such as In2Se3 are easily generated in the traditional solid-state reaction method. Attached Figure Description

[0011] Figure 1 This is an optical photograph of the In2Ge2Se6 single crystal in Example 1.

[0012] Figure 2 The image shows the X-ray diffraction pattern of the In2Ge2Se6 single crystal in Example 1.

[0013] Figure 3 The image shows the X-ray diffraction pattern of the In2Ge2Se6 powder in Example 1.

[0014] Figure 4 This is a scanning electron microscope image of the microstructure of the In2Ge2Se6 single crystal in Example 1.

[0015] Figure 5 The image shows the X-ray energy spectrum of the In2Ge2Se6 single crystal in Example 1.

[0016] Figure 6 This is an atomic resolution structural diagram of the In2Ge2Se6 material [1-100] in Example 1, projected along the direction.

[0017] Figure 7 An optical photograph of the material obtained in Comparative Example 1.

[0018] Figure 8 The X-ray powder diffraction pattern of the material obtained in Comparative Example 1 is shown.

[0019] Figure 9 An optical photograph of the In2Ge2Se6 single crystal in Comparative Example 3. Detailed Implementation

[0020] This invention provides a large-size ternary layered In2Ge2Se6 single crystal 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.

[0021] The first aspect of this invention provides a method for preparing large-size ternary layered In2Ge2Se6 single crystal material, comprising the following steps: S001. Using indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 as raw materials, mix indium powder, germanium powder, and selenium powder in a quartz tube, and add 4-6 mg / mL of iodine particles to make the vacuum degree inside the quartz tube ≤1 Pa, and seal the quartz tube. S002. Place the end of the quartz tube with raw material in the high-temperature zone of the dual-temperature furnace, and the end without raw material in the low-temperature zone of the dual-temperature furnace; raise the temperature to 500±25℃ at the low-temperature zone end and 600±25℃ at the high-temperature zone end; after holding at this temperature range for 5 to 7 days, allow the vacuum-sealed quartz tube to cool naturally to room temperature; clean and dry the grown material to obtain a large-size ternary layered In2Ge2Se6 single crystal material.

[0022] The preparation method of this invention employs chemical vapor transport (CVT) with iodine as the transport agent. Crystal growth is achieved through high-temperature dual-zone CVT, a simple and easily implemented process. Specifically, the temperature of the dual-zone furnace must not be too low during preparation, otherwise the CVT process will not easily occur; the temperature of the dual-zone furnace must also not be too high, otherwise the resulting material will not have a plate-like morphology and will contain a small amount of In2Se3 phase.

[0023] Preferably, the purity of the indium powder, germanium powder, and selenium powder is ≥99.99wt%.

[0024] Preferably, in S002, the heating time is 120-600 min.

[0025] Preferably, in step S002, the material obtained by growth is placed in alcohol for cleaning and drying.

[0026] The second aspect of the present invention provides a large-size ternary layered In2Ge2Se6 single crystal material, which is prepared by the preparation method of the large-size ternary layered In2Ge2Se6 single crystal material as described above.

[0027] Example 1 A method for preparing a large-size ternary layered In2Ge2Se6 single crystal material includes the following steps: Step 1: Ingredient Preparation and Packaging Using indium powder, germanium powder, and selenium powder with a purity of 99.99 wt% as raw materials, indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 were weighed and mixed in a quartz tube. Iodine particles at a concentration of 5 mg / mL were added, and the tube was evacuated to ≤1 Pa. The quartz tube containing the sample was then sealed using a flame sealing device.

[0028] Step 2: High-temperature firing in dual temperature zones The vacuum-sealed quartz tube was placed horizontally in a dual-zone tube furnace, with the raw material concentrated at the sealed end of the tube. This end was placed at the thermocouple in the high-temperature zone of the furnace, while the tip of the tube was placed at the thermocouple in the low-temperature zone. The temperature at the low-temperature zone was controlled at 500°C, and the temperature at the high-temperature zone was controlled at 600°C. The dual-zone tube furnace was heated from room temperature to the specified temperature over 240 minutes and held at that temperature for 5 days. Subsequently, the vacuum-sealed quartz tube was allowed to cool naturally to room temperature. The grown material was then placed in alcohol for cleaning and drying.

[0029] Step 3: Organization and Structure Analysis The morphology, chemical composition, and structure of the obtained materials were analyzed and characterized using optical microscopy, X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and transmission electron microscopy. Figure 1 This is an optical photograph of the In2Ge2Se6 single crystal in Example 1. Figure 2 The image shows the X-ray diffraction pattern of the In2Ge2Se6 single crystal in Example 1. Figure 3 The image shows the X-ray diffraction pattern of the In2Ge2Se6 powder in Example 1. Figure 4 This is a scanning electron microscope image of the microstructure of the In2Ge2Se6 single crystal in Example 1. Figure 5 The image shows the X-ray energy spectrum of the In2Ge2Se6 single crystal in Example 1. Figure 6This is an atomic resolution structural diagram of the In2Ge2Se6 material [1-100] in Example 1, projected along the direction of the image. Based on the theoretically predicted A2M2Q6 structural model, and through analysis of X-ray energy dispersive spectroscopy and X-ray diffraction patterns, its chemical composition was determined to be In2Ge2Se6, and its crystal structure is rhombohedral phase (…). R ). Figure 2 The mid-wave diffraction peaks correspond to the (000) of the In2Ge2Se6 structure, respectively. l () l =3, 6, 9, 12, 15) crystal planes, the material obtained under these conditions is a single crystal material, and the growth orientation is c Axial direction. Scanning electron microscopy shows that this material has layered morphological characteristics. Figure 4 In addition, high-angle annular dark-field images obtained using transmission electron microscopy (TEM) Figure 6 This further demonstrates that the crystal structure of the obtained material is consistent with the A2M2Q6 structural model, exhibiting axial growth characteristics. c A layered structure along the axial direction.

[0030] Example 2 A method for preparing a large-size ternary layered In2Ge2Se6 single crystal material includes the following steps: Step 1: Ingredient Preparation and Packaging Using indium powder, germanium powder, and selenium powder with a purity of 99.99 wt% as raw materials, indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 were weighed and mixed in a quartz tube. Iodine particles at a concentration of 5 mg / mL were added, and the tube was evacuated to ≤1 Pa. The quartz tube containing the sample was then sealed using a flame sealing device.

[0031] Step 2: High-temperature firing in dual temperature zones The vacuum-sealed quartz tube was placed horizontally in a dual-zone tube furnace, with the raw material concentrated at the sealed end of the tube. This end was placed at the thermocouple in the high-temperature zone of the furnace, while the tip of the tube was placed at the thermocouple in the low-temperature zone. The temperature at the low-temperature zone was controlled at 525°C, and the temperature at the high-temperature zone was controlled at 625°C. The dual-zone tube furnace was heated from room temperature to the specified temperature over 250 minutes and held at that temperature for 5 days. Subsequently, the vacuum-sealed quartz tube was allowed to cool naturally to room temperature. The grown material was then placed in alcohol for cleaning and drying.

[0032] Step 3: Organization and Structure Analysis Referring to the analysis process of Example 1, the morphology, chemical composition and structure of the prepared material were analyzed and characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and X-ray energy dispersive spectroscopy, and transmission electron microscopy. It was determined that the material obtained under this condition was an In2Ge2Se6 single crystal material.

[0033] Comparative Example 1 A method for preparing a large-size ternary layered In2Ge2Se6 single crystal material includes the following steps: Step 1: Ingredient Preparation and Packaging Using indium powder, germanium powder, and selenium powder with a purity of 99.99 wt% as raw materials, indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 were weighed and mixed in a quartz tube. Iodine particles at a concentration of 5 mg / mL were added, and the tube was evacuated to ≤1 Pa. The quartz tube containing the sample was then sealed using a flame sealing device.

[0034] Step 2: High-temperature firing in dual temperature zones The vacuum-sealed quartz tube was placed horizontally in a dual-zone tube furnace, with the raw material concentrated at the sealed end of the tube. This end was placed at the thermocouple in the high-temperature zone of the furnace, while the tip of the tube was placed at the thermocouple in the low-temperature zone. The temperature at the low-temperature zone was controlled at 650°C, and the temperature at the high-temperature zone was controlled at 750°C. The dual-zone tube furnace was heated from room temperature to the specified temperature over 300 minutes and held at that temperature for 5 days. Subsequently, the vacuum-sealed quartz tube was allowed to cool naturally to room temperature. The grown material was then placed in alcohol for cleaning and drying.

[0035] Step 3: Organization and Structure Analysis Following the analytical process of Example 1, 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, as well as transmission electron microscopy. The results showed that the obtained material had a blocky rather than sheet-like morphology (e.g., ...). Figure 7 As shown), and it was determined that the material obtained under these conditions included the In2Ge2Se6 phase and a small amount of the In2Se3 phase (as shown). Figure 8 (The significant characteristic diffraction peaks are shown by the arrows), but no In2Ge2Se6 single crystal material was obtained. This comparative example illustrates that In2Ge2Se6 single crystal material cannot be obtained at excessively high temperatures.

[0036] Comparative Example 2 A method for preparing a large-size ternary layered In2Ge2Se6 single crystal material includes the following steps: Step 1: Ingredient Preparation and Packaging Using indium powder, germanium powder, and selenium powder with a purity of 99.99 wt% as raw materials, indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 were weighed and mixed in a quartz tube. Iodine particles at a concentration of 5 mg / mL were added, and the tube was evacuated to ≤1 Pa. The quartz tube containing the sample was then sealed using a flame sealing device.

[0037] Step 2: High-temperature firing in dual temperature zones The vacuum-sealed quartz tube was placed horizontally in a dual-zone tube furnace, with the raw material concentrated at the sealed end of the tube, which was positioned at the thermocouple in the high-temperature zone. The tip of the tube was positioned at the thermocouple in the low-temperature zone. The temperature at the low-temperature zone was controlled at 300°C, and the temperature at the high-temperature zone was controlled at 400°C. The dual-zone tube furnace was heated from room temperature to the specified temperature over 160 minutes and held at that temperature for 5 days. Subsequently, the vacuum-sealed quartz tube was allowed to cool naturally to room temperature. The grown material was then placed in alcohol for cleaning and drying.

[0038] Step 3: Organization and Structure Analysis Following the analysis process of Example 1, the prepared material was analyzed. The results showed that no obvious single crystals were formed in the low-temperature region. This may be because the temperatures in the low-temperature and high-temperature regions of this comparative example are relatively low, making it difficult for gas phase transport processes to occur, thus resulting in no obvious single crystal growth in the low-temperature region under these conditions.

[0039] Comparative Example 3 Step 1: Ingredient Preparation and Packaging Using indium powder, germanium powder, and selenium powder with a purity of 99.99 wt% as raw materials, indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 were weighed and mixed in a quartz tube. Iodine particles of 1 mg / mL were added, and the vacuum was drawn to ≤1 Pa. Then, the quartz tube containing the sample was sealed using a flame sealing device.

[0040] Step 2: High-temperature firing in dual temperature zones The vacuum-sealed quartz tube was placed horizontally in a dual-zone tube furnace, with the raw material concentrated at the sealed end of the tube. This end was placed at the thermocouple in the high-temperature zone of the furnace, while the tip of the tube was placed at the thermocouple in the low-temperature zone. The temperature at the low-temperature zone was controlled at 500°C, and the temperature at the high-temperature zone was controlled at 600°C. The dual-zone tube furnace was heated from room temperature to the specified temperature over 160 minutes and held at that temperature for 5 days. Subsequently, the vacuum-sealed quartz tube was allowed to cool naturally to room temperature. The grown material was then placed in alcohol for cleaning and drying.

[0041] Step 3: Organization and Structure Analysis Following the analytical procedure of Example 1, the prepared material was analyzed. The results showed that the chemical composition of the single-crystal material obtained under these conditions was In₂Ge₂Se₆. However, a comparison with Example 1 revealed that the single-crystal size obtained under these experimental conditions was very small (e.g., ...). Figure 9 This indicates that the concentration of added iodine affects the size of the single crystal.

[0042] In summary, the results of the above examples and comparative examples show that only within a specific dual-temperature range and with a suitable concentration of added iodine can large-size, high-quality ternary layered selenide In2Ge2Se6 semiconductor single crystal materials be prepared.

[0043] 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 large-size ternary layered In2Ge2Se6 single crystal material, characterized in that, Includes the following steps: S001. Using indium powder, germanium powder, and selenium powder in a molar ratio of 2:2:6 as raw materials, mix indium powder, germanium powder, and selenium powder in a quartz tube, and add 4-6 mg / mL of iodine particles to make the vacuum degree inside the quartz tube ≤1 Pa, and seal the quartz tube. S002. Place the end of the quartz tube with raw material in the high-temperature zone of the dual-temperature furnace, and the end without raw material in the low-temperature zone of the dual-temperature furnace; raise the temperature to 500±25℃ at the low-temperature zone end and 600±25℃ at the high-temperature zone end; after holding at this temperature range for 5 to 7 days, allow the vacuum-sealed quartz tube to cool naturally to room temperature; clean and dry the grown material to obtain a large-size ternary layered In2Ge2Se6 single crystal material.

2. The method for preparing large-size ternary layered In2Ge2Se6 single crystal material according to claim 1, characterized in that, The purity of the indium powder, germanium powder, and selenium powder is ≥99.99wt%.

3. The method for preparing large-size ternary layered In2Ge2Se6 single crystal material according to claim 1, characterized in that, In the S002, the heating time is 120-600 min.

4. The method for preparing large-size ternary layered In2Ge2Se6 single crystal material according to claim 1, characterized in that, In step S002, the material obtained by growth is placed in alcohol for cleaning and drying.

5. A large-size ternary layered In₂Ge₂Se₆ single crystal material, characterized in that, It is prepared by the method for preparing large-size ternary layered In2Ge2Se6 single crystal material according to any one of claims 1-4.

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