A physical and chemical vapor transport preparation method of batched high growth rate centimeter level one-dimensional GaSeI single crystal

Abstract

This invention provides a physicochemical vapor-phase transport method for the mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals, comprising: using elemental Ga, Se, and I₂ as raw materials; designating the two ends of a quartz tube as ends A and B, respectively; mixing the raw materials and placing them at end A of the quartz tube; then evacuating and sealing the quartz tube; controlling the temperature of the quartz tube, setting end A as a low-temperature region and end B as a high-temperature region for vapor-phase transport; exchanging the temperature regions, setting end A as a high-temperature region and end B as a low-temperature region for crystal growth; repeating steps S2-S3 n times; after crystal growth is completed, cooling to room temperature to obtain high-purity GaSeI single crystals. This invention, by repeatedly exchanging high-temperature and low-temperature regions for vapor-phase transport, can increase nucleation sites, improve conversion rate and growth quality, increase sample contact area and growth size. Through precise temperature control and precise regulation of the system environment's sealing and vapor-phase reaction balance, high-yield centimeter-scale one-dimensional GaSeI single crystals can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of crystal preparation technology, specifically relating to a physicochemical vapor-phase transport preparation method for mass production of centimeter-scale one-dimensional GaSeI single crystals with high growth rate. Background Technology

[0002] Metal-based sulfur halides encompass three components: metals, chalcogens, and halogens. In recent years, these materials have attracted considerable attention in the optoelectronic field due to their excellent optoelectronic properties, such as flexibly tunable band gaps, outstanding light absorption, and superior carrier mobility, while also being environmentally friendly. For example, PbSeCl₂ is an infrared-transparent material suitable for infrared windows or sensors; SbSI₃ possesses strong ferroelectricity and piezoelectricity, making it suitable for energy conversion devices; and CuSBr exhibits high ionic conductivity, making it a potential candidate material for solid-state electrolytes. GaSeI crystals also hold significant research value.

[0003] Currently, traditional methods for preparing GaSeI crystals include chemical vapor deposition (CVT), solvothermal methods, and mechanical alloying. These processes mainly involve: a low-temperature stage to promote the initial reaction between I₂ and Ga / Se; a medium-temperature stage where the temperature is raised to 400–500°C (below the sublimation points of Se and I) and held for 12–24 hours to form an intermediate phase; and a high-temperature stage where the temperature is rapidly raised to 600–700°C to promote crystallization. However, these methods are costly and complex, the reaction process is difficult to control, and impurities and byproducts are easily introduced, hindering the production of high-quality, high-yield GaSeI crystals. Cordova reported a high-quality GaSeI single crystal prepared by chemical vapor deposition, but the preparation cycle was long (14 days) (Nature Materials, 23, 1347–1354 (2024)). Therefore, developing high-growth-rate, high-volume, and high-quality pure GaSeI crystal preparation techniques and processes is essential for the study and application of this material. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by providing a physicochemical vapor phase transport preparation method for mass production of centimeter-scale one-dimensional GaSeI single crystals with high growth rates, thereby improving growth quality, size, and conversion rate.

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

[0006] This invention provides a physicochemical vapor-phase transport method for the mass production of high-growth-rate, centimeter-scale one-dimensional GaSeI single crystals, comprising the following steps: S1. Using elemental Ga, elemental Se and elemental I2 as raw materials, designate the two ends of the quartz tube as end A and end B respectively. Weigh and mix the raw materials and place them at end A of the quartz tube. Then, evacuate the quartz tube and seal it. S2. Adjust the temperature of the quartz tube, set end A to the low temperature zone and end B to the high temperature zone, and carry out gas phase transport. S3. Exchange temperature zone: Set end A as the high temperature zone and end B as the low temperature zone to carry out crystal growth. S4. Repeat steps S2~S3 n times. After crystal growth is complete, cool to room temperature to obtain high-purity GaSeI single crystal.

[0007] Furthermore, in step S1, the molar ratio of elemental Ga, elemental Se, and elemental I2 is 1:1:(1.01 to 1.05), preferably 1:1:1.02.

[0008] Furthermore, in step S1, the vacuum level inside the quartz tube is 10. -3 ~10 -5 Pa.

[0009] Furthermore, in step S1, after the raw materials are weighed and mixed, they are placed in a quartz tube and then purged with an inert gas. After purging, the vacuum level is controlled to 10 by a vacuum pump. -3 ~10 -5 Pa.

[0010] Furthermore, the temperature difference between the high-temperature zone and the low-temperature zone is 80–120 °C, preferably 100 °C, and the temperature gradient is 0.8–1.2 °C / cm.

[0011] Furthermore, the temperature of the low-temperature zone is set to 350–450 °C, and the temperature of the high-temperature zone is set to 450–550 °C.

[0012] Furthermore, in step S2, the gas phase transport time is 24~72 h; in step S3, the crystal growth time is 12~24 h.

[0013] Furthermore, in step S4, the value of n is 2 to 10.

[0014] Furthermore, in step S4, after the crystal growth is completed, the temperature is reduced to room temperature at a cooling rate of 0.3 to 1 °C / min.

[0015] Furthermore, the heating rate of the high-temperature zone and the low-temperature zone of the quartz tube is 0.5 to 1 °C / min.

[0016] Furthermore, the temperature exchange zone is completed within 1 hour.

[0017] The beneficial effects of this invention are: This invention uses high-purity elemental Ga, Se, and I₂ as raw materials. I₂ in the raw materials serves as both a constituent element of the sample and a gas-phase transport agent in the reaction. By combining chemical vapor transport (CVT) with precise control of the temperature gradient and precise regulation of the system's sealing and gas-phase reaction equilibrium, high-quality, pure GaSeI single crystals can be prepared. Through multiple exchanges between high-temperature and low-temperature regions for gas-phase transport, the number of nucleation sites can be increased, improving growth conversion rate and growth quality, increasing the sample contact area, and improving the growth size. This invention is low in cost and simple in process, the reaction process is easy to control, the growth rate is fast, it is not easy to introduce impurities, and it is easier to obtain high-quality centimeter-sized GaSeI single crystals in large quantities. It is a mass production technology for high-growth-rate centimeter-sized one-dimensional GaSeI single crystals. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the operation process of the present invention; Figure 2 An optical microscope image of the GaSeI single crystal prepared in Example 1 of this invention; Figure 3 The Raman spectrum of the GaSeI single crystal prepared in Example 1 of this invention; Figure 4 This is a SEM image of the GaSeI single crystal prepared in Example 1 of the present invention; Figure 5 The material composition EDS spectrum of the GaSeI single crystal prepared in Example 1 of this invention; Figure 6 An optical microscope image of the GaSeI single crystal prepared in Comparative Example 1 of this invention; Figure 7 An optical microscope image of the GaSeI single crystal prepared in Example 2 of this invention; Figure 8 This is a SEM image of the GaSeI single crystal prepared in Example 2 of the present invention; Figure 9 The material composition EDS spectrum of the GaSeI single crystal prepared in Example 2 of this invention; Figure 10 An optical microscope image of the GaSeI single crystal prepared in Comparative Example 3 of this invention; Figure 11 An optical microscope image of the GaSeI single crystal prepared in Example 3 of this invention; Figure 12 This is a SEM image of the GaSeI single crystal prepared in Example 3 of the present invention; Figure 13 This is an optical microscope image of the GaSeI single crystal prepared in Comparative Example 4 of this invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a physicochemical vapor transport method for the mass production of centimeter-scale one-dimensional GaSeI single crystals with high growth rates. Based on high-purity elemental Ga, Se, and I2 as raw materials, the method combines chemical vapor transport (CVT), precise control of temperature gradient, and precise regulation of system environmental sealing and vapor phase reaction equilibrium to prepare GaSeI single crystals.

[0021] Preparation method see Figure 1 Specifically, it includes the following steps: Step 1: Take a quartz tube and ultrasonically clean it sequentially with acetone and deionized water for 30 minutes, then dry it. Designate the two ends of the quartz tube as end A and end B, respectively. Weigh and uniformly mix elemental Ga, elemental Se, and elemental I₂ ​​in a molar ratio of 1:1:(1.01~1.05), place the mixture at end A of the quartz tube, and purge with an inert gas. After purging, control the vacuum level using a vacuum pump, ultimately maintaining a vacuum level of 10. -3 ~10 -5 Pa, and finally sealed the tube with an oxyhydrogen flame.

[0022] Step 2: Place the sealed quartz tube into a dual-temperature zone tube furnace. Adjust the furnace temperature so that end A of the quartz tube is in the low-temperature zone and end B is in the high-temperature zone. Perform gas-phase transport for 24–72 hours. The temperature difference between the high-temperature and low-temperature zones is 80–120 °C, preferably 100 °C, with a temperature gradient of 0.8–1.2 °C / cm. If the temperature difference is too low, the transport momentum will be insufficient, and GaSeI single crystals cannot be formed; if the temperature difference is too large, GaSeI polycrystalline crystals will be formed.

[0023] In a preferred embodiment of the present invention, the temperature of the low-temperature zone is set to 350–450 °C, and the temperature of the high-temperature zone is set to 450–550 °C. Excessive temperature will cause the iodine vapor pressure to become too high and break the quartz tube, while excessively low temperature will affect the reaction. To prevent the I2 vapor pressure from becoming too high and ultimately causing the quartz tube to crack, the heating rate can be controlled to be 0.5–1 °C / min.

[0024] Step 3: Switch the temperature to exchange temperature zones, that is, set end A to the high-temperature zone and end B to the low-temperature zone, and perform crystal growth for 12-24 hours. The temperature zone exchange is completed within 1 hour.

[0025] Step 4: Repeat steps 2-3 2-10 times to improve the purity of GaSeI crystal. After the crystal growth is completed, cool down to room temperature at a cooling rate of 0.3-1℃ / min to obtain a high-purity GaSeI single crystal. Cut the quartz tube and take out the GaSeI single crystal at the low-temperature end.

[0026] Example 1 This embodiment provides a physicochemical vapor phase transport method for the mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals, including the following steps: Step 1: Loading raw materials into the tube Elemental Ga, elemental Se, and elemental I2 were weighed in a molar ratio of 1:1:1.02. Specifically, 1.3945 g of Ga (actual mass 1.3995 g), 1.5792 g of Se (actual mass 1.5785 g), and 2.5381 g of I2 (actual mass 2.5219 g) were taken and mixed evenly.

[0027] Take a quartz tube and ultrasonically clean it sequentially with acetone and deionized water for 30 minutes each, then dry it. Designate the two ends of the quartz tube as end A and end B, respectively. In an argon-protected glove box, transfer the uniformly mixed raw material to end A of the quartz tube, then purge it with an inert gas. After purging, control the vacuum level using a vacuum pump, ultimately maintaining a vacuum level of 10. -5 Pa, and finally sealed the tube with an oxyhydrogen flame.

[0028] Step 2: Gas Phase Transport The sealed quartz tube was placed horizontally in a dual-temperature zone tube furnace for heating, with end A of the quartz tube in the low-temperature zone and end B in the high-temperature zone. The temperature in the low-temperature zone was raised to 450 °C at a heating rate of 0.7 °C / min, and the temperature in the high-temperature zone was raised to 550 °C at a heating rate of 0.7 °C / min for gas phase transport. The heating treatment time was 72 h.

[0029] Step 3: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 24 hours.

[0030] Step 4: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0031] Step 5: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 24 hours.

[0032] Step 6: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0033] Step 7: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 24 hours.

[0034] Step 8: Collect crystals After passing through three temperature exchange zones, the quartz tube A was cooled to room temperature at a rate of 0.7℃ / min to obtain a high-purity GaSeI single crystal. The quartz tube was then cut, and the GaSeI single crystal was removed from the low-temperature zone end.

[0035] Figure 2 This is an optical microscope image of the GaSeI single crystal prepared in Example 1.

[0036] Figure 3 The image shows the Raman spectrum of the GaSeI single crystal prepared in Example 1. The Raman test shows that the Raman spectrum of the sample obtained in Example 1 is consistent with that of GaSeI.

[0037] Figure 4 The image shows the SEM morphology of the GaSeI single crystal prepared in Example 1. The sample exhibits a single crystal orientation.

[0038] Figure 5 Table 1 shows the EDS energy dispersive spectroscopy results of the GaSeI single crystal prepared in Example 1. The results show that the atomic ratio of Ga, Se and I in the obtained sample is close to 1:1:1, indicating that this method can indeed obtain high-purity GaSeI single crystals.

[0039] Table 1: EDS energy dispersive spectroscopy results of GaSeI single crystals prepared in Example 1

[0040] Example 2 This embodiment provides a physicochemical vapor phase transport method for the mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals. The difference from the previous embodiment lies in that this embodiment involves five temperature zone exchanges, specifically including the following steps: Step 1: Loading raw materials into the tube Elemental Ga, elemental Se, and elemental I2 were weighed in a molar ratio of 1:1:1.02. Specifically, 2.7893 g of Ga (actual mass 2.7919 g), 3.1584 g of Se (actual mass 3.1815 g), and 5.0762 g of I2 (actual mass 5.1173 g) were taken and mixed evenly.

[0041] Take a quartz tube and ultrasonically clean it sequentially with acetone and deionized water for 30 minutes each, then dry it. Designate the two ends of the quartz tube as end A and end B, respectively. In an argon-protected glove box, transfer the uniformly mixed raw material to end A of the quartz tube, then purge it with an inert gas. After purging, control the vacuum level using a vacuum pump, ultimately maintaining a vacuum level of 10. -5 Pa, and finally sealed the tube with an oxyhydrogen flame.

[0042] Step 2: Gas Phase Transport The sealed quartz tube was placed horizontally in a dual-temperature zone tube furnace for heating, with end A of the quartz tube in the low-temperature zone and end B in the high-temperature zone. The temperature in the low-temperature zone was raised to 450 °C at a heating rate of 0.8 °C / min, and the temperature in the high-temperature zone was raised to 550 °C at a heating rate of 0.8 °C / min for gas phase transport. The heating treatment time was 72 h.

[0043] Step 3: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 12 hours.

[0044] Step 4: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0045] Step 5: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 24 hours.

[0046] Step 6: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0047] Step 7: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 24 hours.

[0048] Step 8: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0049] Step 9: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 24 hours.

[0050] Step 10: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0051] Step 11: Exchange temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 24 hours.

[0052] Step 12: Collect crystals After passing through five temperature exchange zones, the quartz tube A was cooled to room temperature at a rate of 0.6℃ / min to obtain a high-purity GaSeI single crystal. The quartz tube was then cut, and the GaSeI single crystal was removed from the low-temperature zone end.

[0053] Figure 7 This is an optical microscope image of the GaSeI single crystal prepared in Example 2.

[0054] Figure 8 The image shows the SEM morphology of the GaSeI single crystal obtained in Example 2, with the sample exhibiting a single crystal orientation.

[0055] Figure 9 Table 2 shows the EDS test results. The atomic ratio of Ga, Se, and I in the sample is close to 1:1:1, indicating that this method did indeed obtain high-purity GaSeI single crystals.

[0056] Table 2: EDS energy dispersive spectroscopy results of GaSeI single crystals prepared in Example 2

[0057] Example 3 This embodiment provides a physicochemical vapor phase transport method for the mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals. The difference from the previous embodiment lies in that this embodiment involves four temperature zone exchanges, specifically including the following steps: Step 1: Loading raw materials into the tube Elemental Ga, elemental Se, and elemental I2 were weighed in a molar ratio of 1:1:1.02. Specifically, 5.5778 g of Ga (actual mass 5.5793 g), 6.3168 g of Se (actual mass 6.3211 g), and 10.1524 g of I2 (actual mass 10.1539 g) were taken and mixed evenly.

[0058] Take a quartz tube and ultrasonically clean it sequentially with acetone and deionized water for 30 minutes each, then dry it. Designate the two ends of the quartz tube as end A and end B, respectively. In an argon-protected glove box, transfer the uniformly mixed raw material to end A of the quartz tube, then purge it with an inert gas. After purging, control the vacuum level using a vacuum pump, ultimately maintaining a vacuum level of 10. -4 Pa, and finally sealed the tube with an oxyhydrogen flame.

[0059] Step 2: Gas Phase Transport The sealed quartz tube was placed horizontally in a dual-temperature zone tube furnace for heating, with end A of the quartz tube in the low-temperature zone and end B in the high-temperature zone. The temperature in the low-temperature zone was raised to 450 °C at a rate of 0.5 °C / min, and the temperature in the high-temperature zone was raised to 550 °C at a rate of 0.5 °C / min for gas phase transport. The heating treatment time was 72 h.

[0060] Step 3: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 18 hours.

[0061] Step 4: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0062] Step 5: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 18 hours.

[0063] Step 6: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0064] Step 7: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 18 hours.

[0065] Step 8: Gas Phase Transport The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, so that the temperature of end A of the quartz tube is reduced to 450°C and the temperature of end B of the quartz tube is increased to 550°C for gas phase transport. The heating treatment time is 72 hours.

[0066] Step 9: Change temperature zones The temperature switching between the high-temperature zone and the low-temperature zone is completed within 1 hour, raising the temperature of end A of the quartz tube to 550°C and lowering the temperature of end B of the quartz tube to 450°C for crystal growth, which takes 18 hours.

[0067] Step 10: Collect crystals After passing through four temperature exchange zones, the quartz tube A was cooled to room temperature at a rate of 0.8℃ / min to obtain a high-purity GaSeI single crystal. The quartz tube was then cut, and the GaSeI single crystal was removed from the low-temperature zone end.

[0068] Figure 11 This is an optical microscope image of the GaSeI single crystal prepared in Example 3.

[0069] Figure 12 The image shows the SEM morphology of the GaSeI single crystal obtained in Example 3, with the sample exhibiting a single crystal orientation.

[0070] Table 3 shows the EDS test results. The atomic ratio of Ga, Se, and I in the sample is close to 1:1:1, indicating that this method did indeed produce high-purity GaSeI single crystals.

[0071] Table 3: EDS energy dispersive spectroscopy results of GaSeI single crystals prepared in Example 3

[0072] Comparative Example 1 Comparative Example 1 provides a method for preparing GaSeI single crystals, which differs from Example 1 in that it does not include an exchange temperature zone. The method specifically includes the following steps: Step 1: Loading raw materials into the tube Elemental Ga, elemental Se, and elemental I2 were weighed in a molar ratio of 1:1:1.02. Specifically, 1.3945 g of Ga (actual mass 1.3899 g), 1.5792 g of Se (actual mass 1.5755 g), and 2.5381 g of I2 (actual mass 2.5339 g) were taken and mixed evenly.

[0073] Take a quartz tube and ultrasonically clean it sequentially with acetone and deionized water for 30 minutes each, then dry it. Designate the two ends of the quartz tube as end A and end B, respectively. In an argon-protected glove box, transfer the uniformly mixed raw material to end A of the quartz tube, then purge it with an inert gas. After purging, control the vacuum level using a vacuum pump, ultimately maintaining a vacuum level of 10. -5 Pa, and finally sealed the tube with an oxyhydrogen flame.

[0074] Step 2: Crystal Growth The sealed quartz tube was horizontally placed in a dual-temperature zone tube furnace for heating, with end A in the low-temperature zone and end B in the high-temperature zone. The temperature was increased to 450 °C at a rate of 0.7 °C / min in the low-temperature zone and to 550 °C at a rate of 0.7 °C / min in the high-temperature zone for growth. The heating treatment lasted for 72 hours. After crystal growth, the temperature was reduced to room temperature at a rate of 0.7 °C / min.

[0075] Figure 6 The sample spectrum prepared for Comparative Example 1 was obtained by... Figure 6 It can be seen that Comparative Example 1 did not employ multiple exchanges between the high-temperature and low-temperature regions for gas-phase transport, and therefore failed to obtain a pure GaSeI single crystal.

[0076] Comparative Example 2 Comparative Example 1 provides a method for preparing GaSeI single crystals, which differs from Example 1 in that it includes a water bath heating operation and does not involve multiple temperature exchange zones. Specifically, it includes the following steps: Step 1: Loading raw materials into the tube Elemental Ga, elemental Se, and elemental I2 were weighed and placed into a reaction vessel in a molar ratio of 1:1:1.02. Specifically, 1.3945 g of Ga (actual mass 1.3899 g), 1.5792 g of Se (actual mass 1.5755 g), and 2.5381 g of I2 (actual mass 2.5339 g) were weighed.

[0077] Take a quartz tube and ultrasonically clean it sequentially with acetone and deionized water for 30 minutes each, then dry it. Designate the two ends of the quartz tube as end A and end B, respectively. In an argon-protected glove box, transfer the raw material to end A of the quartz tube, then purge it with an inert gas. After purging, control the vacuum level using a vacuum pump, ultimately maintaining a vacuum level of 10.-5 Pa, and finally sealed the tube with an oxyhydrogen flame.

[0078] Step 2: Water bath heating The raw materials were mixed evenly using a water bath heating method. The raw material end (end A) of the quartz tube was placed vertically in a constant temperature water bath for high-temperature treatment, with the temperature set at 450℃. The temperature was increased from room temperature to the set temperature at a rate of 0.7℃ / min and maintained for 48 hours, and then decreased from the high temperature to room temperature at a rate of 1.2℃ / min.

[0079] Step 3: Reverse transport The quartz tube is placed horizontally in a dual-temperature zone tube furnace for heating, with end A of the quartz tube set in the low-temperature zone (450 ℃) and end B set in the high-temperature zone (550 ℃), and is transported in reverse order. The heating treatment time is 48 h.

[0080] Step 4: Temperature Switching The high and low temperature switching was completed within 1 hour. One end containing the raw material (end A of the quartz tube) was heated to 550℃, while the other end (end B of the quartz tube) was cooled to 450℃ for growth. The heat treatment time was 168 hours. After crystal growth, the temperature was lowered to room temperature at a rate of 0.7℃ / min. Finally, GaSeI single crystals were obtained from the low-temperature end.

[0081] Comparative Example 2 did not employ gas-phase transport through multiple exchanges between high-temperature and low-temperature regions. In this comparative example, the molar ratio of Ga, Se, and I elements deviated significantly from 1:1:1.02, and a pure GaSeI single crystal was not obtained.

[0082] Comparative Example 3 Comparative Example 1 provides a method for preparing GaSeI single crystals, which differs from Example 2 in that... In step 1 of Comparative Example 3, the vacuum level inside the quartz tube is controlled at 10. -2 Pa.

[0083] Figure 10 The sample spectrum prepared for Comparative Example 3 was obtained by... Figure 10 It can be seen that the molar ratio of Ga, Se, and I in Comparative Example 3 deviates significantly from 1:1:1.02, and pure GaSeI single crystals were not obtained.

[0084] Comparative Example 4 Comparative Example 4 provides a method for preparing GaSeI single crystals, which differs from Example 3 in that: The temperature in the low-temperature zone is set to 200℃.

[0085] Figure 13 The sample spectrum prepared for Comparative Example 4 was obtained by... Figure 13It can be seen that the preparation temperature of the low-temperature end in Comparative Example 4 was too low, and pure GaSeI single crystals were not obtained.

[0086] In this invention, elemental Ga, elemental Se, and elemental I2 are used as raw materials. GaSeI single crystals are prepared by gas-phase transport through multiple exchanges between high-temperature and low-temperature regions. This increases the number of nucleation sites, improves the conversion rate and growth quality, and increases the sample contact area and growth size. Through precise temperature control and precise regulation of the system environment sealing and gas-phase reaction balance, the length of the obtained one-dimensional GaSeI crystal can reach 3~7cm. Finally, a high yield (1~20g) of centimeter-scale one-dimensional GaSeI single crystals can be obtained within 1~5 days.

[0087] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A physicochemical vapor-phase transport method for the mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals, characterized in that, Includes the following steps: S1. Using elemental Ga, elemental Se, and elemental I2 as raw materials, designate the two ends of the quartz tube as end A and end B respectively. After mixing the raw materials, place them at end A of the quartz tube, and then evacuate and seal the quartz tube. S2. Adjust the temperature of the quartz tube, set end A to the low temperature zone and end B to the high temperature zone, and carry out gas phase transport. S3. Exchange temperature zone: Set end A as the high temperature zone and end B as the low temperature zone to carry out crystal growth. S4. Repeat steps S2~S3 n times. After crystal growth is complete, cool to room temperature to obtain high-purity GaSeI single crystal.

2. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, In step S1, the molar ratio of elemental Ga, elemental Se, and elemental I2 is 1:1:(1.01~1.05).

3. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, In step S1, the vacuum level inside the quartz tube is 10. -3 ~10 -5 Pa.

4. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, The temperature difference between the high-temperature zone and the low-temperature zone is 80–120 °C, and the temperature gradient is 0.8–1.2 °C / cm.

5. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 4, characterized in that, The temperature of the low-temperature zone is set to 350–450 °C, and the temperature of the high-temperature zone is set to 450–550 °C.

6. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, In step S2, the gas phase transport time is 24~72 h; In step S3, the crystal growth time is 12~24 h.

7. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, In step S4, the value of n is 2 to 10.

8. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, In step S4, after crystal growth is completed, the temperature is reduced to room temperature at a rate of 0.3 to 1 °C / min.

9. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, The heating rate of the high-temperature zone and the low-temperature zone of the quartz tube is 0.5 to 1 °C / min.

10. The physicochemical vapor phase transport preparation method for mass production of high-growth-rate centimeter-scale one-dimensional GaSeI single crystals according to claim 1, characterized in that, The temperature exchange zone is completed within 1 hour.

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