Preparation method of multi-compound semiconductor crystal

Abstract

The invention relates to the field of II-VI group compound semiconductor material preparation, and discloses a preparation method of a polycompound semiconductor crystal, the polycompound semiconductor crystal is a selenium tellurium magnesium cadmium crystal, the chemical formula is Cd < 0.95 > Mg < 0.05 > Te < 1-x > Se < x >, the preparation method sequentially comprises the following steps: synthesizing a selenium tellurium magnesium cadmium polycrystal material by a high-temperature melting method, carrying out crystal growth by a vertical Bridgman method, and carrying out in-situ annealing treatment. The preparation raw materials comprise basic raw materials of Cd, Mg, Te and Se which are proportioned according to the stoichiometric ratio of Cd0. 95Mg0. 05Te1-xSex, excessive Te is added on the basis of the basic raw materials, and the In element is doped. The selenium tellurium magnesium cadmium single crystal is grown by adopting a three-temperature-zone crystal growth furnace in combination with a vertical Bridgman method, so that the temperature gradient can be accurately regulated and controlled, a smoother solid-liquid interface can be formed, the generation of defects such as dislocation, twin crystal and inclusion in the crystal is effectively reduced, meanwhile, the thermal stress in the crystal growth process is reduced, and the crystal quality is improved. The mechanical stability of the crystal is improved.

Description

Technical Field

[0001] This invention relates to the field of II-VI group compound semiconductor material preparation, specifically a method for preparing multi-component compound semiconductor crystals. Background Technology

[0002] Room temperature radiation detectors have irreplaceable application value in many key areas of national economy and national security, such as medical imaging, security inspection, nuclear safety monitoring, and industrial non-destructive testing. Their performance directly depends on the physicochemical and electrical properties of the core semiconductor materials. II-VI group compound semiconductor crystals have become the preferred materials for fabricating room temperature radiation detectors due to their moderate bandgap, high bulk resistivity, large X-ray absorption coefficient, and excellent carrier mobility-lifetime product. Detectors made from such materials do not require cryogenic cooling equipment and have advantages such as small size, low power consumption, and high detection efficiency. Therefore, the research and development of related crystal material preparation technology has always been a key research focus in the field of semiconductor materials.

[0003] Among numerous II-VI group compound semiconductor crystals, cadmium magnesium telluride (CdMgTe) crystals have become an important research direction for room temperature radiation detectors due to their high density, high effective mass, high resistivity, and excellent electronic transport properties. However, many problems still need to be solved in their actual preparation and application. For example, the intrinsic hardness of the crystal is relatively low, making it prone to breakage during processing and use. Furthermore, structural defects such as dislocations and twins are easily formed during crystal growth. At the same time, intrinsic defects such as Te vacancies and Cd vacancies, as well as the formation and aggregation of Te inclusions, can seriously affect the compositional uniformity and electrical properties of the crystal, thus limiting its application in high-performance detectors. Research has found that introducing a small amount of Se into CdTe-based ternary compound semiconductors can improve the overall hardness of the crystal through solid solution hardening. At the same time, the segregation coefficient of Se approaches 1, which can effectively improve the axial and radial compositional uniformity of the crystal and suppress the formation of intrinsic defects and inclusions. Therefore, CdMgTe ternary compound semiconductor crystals have become a potential room temperature radiation detector material with both high hardness and excellent electrical properties, attracting widespread attention in the industry.

[0004] Currently, the vertical Bridgman process is widely used to prepare CdTe-based compound semiconductor crystals. This method has become the mainstream crystal growth technology due to its simple process principle and ability to grow large-size crystals. However, existing technologies mostly use two-temperature zone crystal growth furnaces to implement this method. Two-temperature zone furnaces consist of only a high-temperature zone and a low-temperature zone, and the temperature gradient adjustment space is limited, making it difficult to achieve precise control. This easily leads to the formation of a curved solid-liquid interface, which not only increases the number of defects such as dislocations and twins in the crystal, but also significantly increases the probability of crystal cracking due to excessive thermal stress. At the same time, a fixed temperature gradient is prone to causing crystal composition segregation, resulting in uneven element distribution and reducing the overall quality of the crystal. Furthermore, in existing CdTe-based crystal preparation processes, polycrystalline material synthesis and crystal growth often need to be completed in different equipment or crucibles. During the transfer process, the raw materials are easily contaminated by the environment or equipment, introducing impurities and defects, which further deteriorates the physical and chemical properties of the crystal. Although some preparation processes attempt to integrate polycrystalline synthesis and crystal growth, the parameter settings of the process steps lack coordination, the links between each step are not smooth, and there are no targeted post-processing steps. The residual stress and micro-defects inside the crystal cannot be effectively eliminated, making it difficult to prepare high-quality single-crystal materials.

[0005] On the other hand, existing CdTe-based multi-component compound semiconductor crystal fabrication processes are complex and require sophisticated equipment. Some processes, in pursuit of crystal quality, involve cumbersome raw material pretreatment and process control steps, which not only increase production costs but also reduce process controllability and repeatability, hindering large-scale industrial production. Furthermore, there are currently no mature fabrication processes reported for novel multi-component compound semiconductor crystals such as selenium tellurium magnesium cadmium. Existing CdTe-based ternary crystal fabrication methods cannot be directly adapted to the growth requirements of selenium tellurium magnesium cadmium crystals. If these methods are directly applied, problems such as elemental imbalance, unstable crystal growth interfaces, and excessive defects may occur, making it impossible to fabricate selenium tellurium magnesium cadmium single crystals that meet the requirements for room temperature radiation detectors.

[0006] In summary, developing a method for preparing multi-component compound semiconductor crystals with a reasonable process design, simple operation, and controllable cost can achieve high-quality, large-scale preparation of magnesium cadmium selenide telluride single crystals. This method effectively solves the problems of numerous defects, uneven composition, easy contamination of raw materials, and poor process synergy in the existing CdTe-based crystal preparation process, and has become a technical challenge that urgently needs to be solved in the field of II-VI compound semiconductor materials. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for preparing multi-component compound semiconductor crystals, which solves the problems mentioned in the background section.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a multi-component compound semiconductor crystal, characterized in that the multi-component compound semiconductor crystal is a magnesium cadmium selenide telluride crystal with the chemical formula Cd. 0.95 Mg 0.05 Te 1-x Se x The preparation method includes the following steps in sequence: high-temperature melting method for synthesizing selenium tellurium magnesium cadmium polycrystalline material, vertical Bridgman method for crystal growth, and in-situ annealing treatment. The raw materials for preparation contain Cd 0.95 Mg 0.05 Te 1-x Se x The basic raw materials of Cd, Mg, Te and Se are stoichiometrically proportioned, with an excess of Te added to the basic raw materials, and also doped with In. The crystal growth is carried out in a three-temperature zone crystal growth furnace. The high temperature zone of the three-temperature zone crystal growth furnace is 1110-1140℃, the medium temperature zone is 1060-1090℃, and the low temperature zone is 750-800℃. The crucible descent rate during the crystal growth process is 0.5-1mm / h.

[0009] Preferably, the Cd 0.95 Mg 0.05 Te 1-x Se x The atomic content of Se in the crystal is 0-4 at%, and the temperature gradient of the three-temperature zone crystal growth furnace is 10-15 K / cm.

[0010] Preferably, the excess Te has a molar fraction of 0.5% and the In element doping volume concentration is 10 ppm.

[0011] Preferably, the process parameters for the high-temperature melting method are: vacuum degree (5-6) × 10 -5 Pa, melting temperature 1100-1150℃, holding time 48h.

[0012] Preferably, the purity of the Cd, Mg, Te, and Se raw materials is 5N-7N, the purity of the In element raw material is 7N, and the crucible used in the preparation is a 6N high-purity quartz crucible coated with a carbon film.

[0013] Preferably, the specific process of crystal growth using the vertical Bridgman method is as follows: after heating to the set temperature in three temperature zones for 10-20 hours, the temperature is held for 12-16 hours to completely melt the polycrystalline material. The crucible is lowered and rotated synchronously, and the total crystal growth time is 110-220 hours.

[0014] Preferably, the process parameters for the in-situ annealing treatment are: annealing temperature 500℃, annealing time 120-240h, after annealing, the power supply to the growth furnace is turned off, and the crystal is cooled to room temperature with the furnace.

[0015] Preferably, the specific steps for synthesizing polycrystalline materials using the high-temperature melting method are as follows: After loading all the proportioned raw materials into the quartz crucible, a molecular pump is used to evacuate to the set vacuum level, and the quartz crucible is then melt-sealed. The sealed crucible is placed in a gyratory furnace, degassed at a low temperature for 12-16 hours, then gradually heated to the melting temperature, held at the temperature and periodically gyrated to promote melt convection, and finally cooled to room temperature with the furnace to obtain polycrystalline material.

[0016] Preferably, the crystal is a selenium tellurium magnesium cadmium single crystal with a diameter of not less than 30 mm and a resistivity of not less than [missing information]. The microhardness is not less than 0.41 GPa, and the infrared transmittance is not less than 60%.

[0017] This invention provides a method for preparing multi-component compound semiconductor crystals. It has the following beneficial effects: 1. This preparation method uses a three-temperature zone crystal growth furnace combined with the vertical Bridgman process to grow magnesium cadmium selenide telluride single crystals. This allows for precise control of the temperature gradient, resulting in a smoother solid-liquid interface. This effectively reduces the generation of defects such as dislocations, twins, and inclusions in the crystal, while also reducing thermal stress during crystal growth, improving the mechanical stability of the crystal, reducing the generation of crystal cracks, and reducing component segregation. This improves the uniformity of element distribution in the crystal, thereby ensuring that the obtained magnesium cadmium selenide telluride single crystals have excellent crystal quality.

[0018] 2. This preparation method introduces Se element into the raw material system and adds excess Te and dopes In element. The introduction of Se element can play a solid solution hardening role to improve the overall hardness of the crystal, while improving the compositional uniformity of the crystal and inhibiting the formation and aggregation of intrinsic defects and inclusion phases in the crystal. The addition of excess Te and doping of In element can further optimize the electrical properties of the crystal. The ratio of each raw material and the doping design are coordinated to make the prepared selenium tellurium magnesium cadmium single crystal meet the performance requirements of semiconductor materials and adapt to the preparation requirements of room temperature nuclear radiation detectors.

[0019] 3. This preparation method integrates high-temperature melting synthesis of polycrystalline material, vertical Bridgman crystal growth, and in-situ annealing into a single process design. Polycrystalline material synthesis and crystal growth are completed in the same crucible, effectively avoiding contamination of raw materials during transfer. At the same time, the parameter settings of each process step are matched and smoothly connected. In-situ annealing can further optimize the internal structure of the crystal. Moreover, the overall preparation process is simple to operate and highly controllable, requiring no complex equipment or operating procedures, which helps to reduce production costs and realize the large-scale preparation of selenium tellurium magnesium cadmium single crystals. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a crystal growth device; Figure 2 Cd in Examples 1 and 2 0.95 Mg 0.05 Te, Cd 0.95 Mg 0.05 Te 0.98 Se 0.02 IV test results of the crystal; Figure 3 Cd in Examples 1 and 2 0.95 Mg 0.05 Te, Cd 0.95 Mg 0.05 Te 0.98 Se 0.02 IR test results of the crystal; Figure 4 Cd in Examples 1 and 2 0.95 Mg 0.05 Te, Cd 0.95 Mg 0.05 Te 0.98 Se 0.02 Energy spectral response test results of the crystal; Figure 5 Cd in Examples 1 and 2 0.95 Mg 0.05 Te, Cd 0.95 Mg 0.05 Te 0.98 Se 0.02 Load (P)-correlation microhardness (Hv) plot of crystal. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0022] Please see the appendix Figure 1 - Appendix Figure 5 The preparation method of the single crystal material of selenium tellurium magnesium cadmium of the present invention includes preparing polycrystalline material of selenium tellurium magnesium cadmium using a high-temperature melting method, and then growing the polycrystalline material of selenium tellurium magnesium cadmium using the vertical Bridgman method. The raw materials for preparation include: in stoichiometric proportions, satisfying the requirements of Cd 0.95 Mg 0.05 Te 1-x Se x The process uses Cd, Mg, Te, and Se as basic raw materials, with excess Te added and then In doped. The three-temperature zone vertical Bridgman process has a high-temperature zone of 1110-1140℃, a medium-temperature zone of 1060-1090℃, and a low-temperature zone of 750-800℃, with a descent rate of 0.5-1 mm / h. Using Cd... 0.95 Mg 0.05 Te 0.98 Se 0.02 For example, the excess Te has a molar fraction of 0.5% and the In doping volume concentration is 10 ppm; The vacuum degree of the high-temperature melting method is (5-6)×10 -5 Pa, temperature 1100-1150℃. The purity of Cd, Mg, Te, and Se is 5N-7N, and the purity of In is 7N. The crystal growth time using the vertical Bridgman process is 110-220 h. The single crystal material obtained after crystal growth is also subjected to in-situ annealing treatment, with an annealing time of 120-240 h and an annealing temperature of 500℃.

[0023] Combination Figure 1 The preparation method of the selenium tellurium magnesium cadmium single crystal material of the present invention includes the following steps: 1. According to the stoichiometric ratio, the Cd... 0.95 Mg 0.05 Te 1-x Se x High-purity Cd, Mg, Te, and Se raw materials (purity 5N-7N) are placed into a high-purity quartz crucible (purity 6N) coated with a carbon film, then 0.5 at% excess Te is added, and finally high-purity metallic In (purity 7N) with a volume concentration of 10 ppm is added. 2. Evacuate the quartz crucible filled with materials using a molecular pump until the vacuum level reaches (5-6)×10⁻⁶. -5 At Pa, the quartz crucible is sealed. The sealed quartz crucible is then placed into a gyratory furnace to mix the materials. The mixing temperature is 1100-1150℃. After holding at this temperature for 48 hours, the furnace is turned off and cooled to room temperature to obtain selenium tellurium magnesium cadmium polycrystalline material. 3. The support end of the quartz crucible containing polycrystalline material is placed onto the support frame in a three-temperature zone crystal growth furnace. The furnace parameters are set, and crystal growth is performed using the vertical Bridgman method. First, after 10-20 hours in the high-temperature zone, medium-temperature zone, and low-temperature zone of the furnace, the temperatures are raised to 1110-1140℃, 1060-1090℃, and 750-800℃ respectively to obtain a melt, which is then held for 12 hours. Then, the quartz crucible is lowered and rotated simultaneously at a rate of 0.5-1 mm / h, allowing the selenium-tellurium-cadmium crystal to grow from the bottom of the crucible. After 110-220 hours of crystal growth, the furnace is simultaneously cooled to 500℃ at a certain rate. Finally, in-situ annealing is performed for 120-240 hours, after which the power is turned off for furnace cooling, yielding a single crystal of selenium-tellurium-cadmium.

[0024] The crystal growth method of the present invention is applicable to the growth of magnesium cadmium selenide telluride crystals with different Se contents. The present invention will be further illustrated below with reference to specific embodiments.

[0025] Example 1: According to Cd 0.95 Mg 0.05 According to the stoichiometry of Te, 146.14 g, 1.76 g, and 184.32 g of high-purity Cd, Mg, and Te raw materials were weighed respectively. An excess Te with a molar fraction of 0.5 at% and In with a volume concentration of 10 ppm and a purity of 7N were added to the base raw materials as dopant elements. The mixture was then placed into a pre-treated high-purity quartz crucible. The crucible was evacuated to (5-6) × 10⁻⁶ using a molecular pump. -5 Pa, the top of a quartz crucible was sealed with an oxyhydrogen flame, and the sealed crucible was placed in a swing furnace. After degassing at low temperature for 12 hours, the temperature was gradually increased to 1100℃, held for 48 hours, and periodically swung to promote melt convection. Then, the crucible was slowly cooled to room temperature with the furnace to obtain magnesium cadmium telluride polycrystalline material. The crucible containing the polycrystalline material was installed on a vertical Bridgman growth furnace support, and the temperature was increased for 10 hours to reach 1119℃ in the high-temperature zone and 750℃ in the low-temperature zone. The temperature was held for 12 hours to completely melt the polycrystalline material. The crucible was lowered and rotated synchronously at a rate of 1 mm / h and the growth continued for 200 hours. The crystal started to grow from the bottom of the crucible. After the crystal growth was completed, the growth furnace was controlled to cool down to 500℃ and in-situ annealing was performed for 120 hours. After annealing, the power was turned off and the crystal was allowed to cool to room temperature with the furnace to obtain magnesium cadmium telluride single crystal.

[0026] Using the above method, Cd atoms with a diameter of 30 mm and a length of 100 mm were successfully grown. 0.95 Mg 0.05 Te single crystal. IV tests show that the resistivity is (See Figure 2 IR testing showed that the infrared transmittance was approximately 60% (see...). Figure 3 Energy spectral response tests show that Cd 0.95 Mg0.05 A room-temperature radiation detector fabricated from a Te ingot head crystal achieves an energy resolution of 18.03% (500V) at the optimal bias voltage (see...). Figure 4 Microhardness testing showed that Cd 0.95 Mg 0.05 The hardness of Te crystal is Hv = 0.41 GPa (see...) Figure 5 ).

[0027] Example 2: According to Cd 0.95 Mg 0.05 Te 0.98 Se 0.02 Stoichiometry was applied, and 143.22 g, 1.72 g, 179.84 g, and 2.46 g of elemental Cd, Mg, Te, and Se were weighed respectively. Excess Te with a molar fraction of 0.5 at% and In with a volume concentration of 10 ppm and a purity of 7N were added as dopant elements to the base materials. The mixture was then placed into a prepared high-purity quartz crucible. A vacuum was drawn to (5-6) × 10⁻⁶. -5 Pa was used to seal the crucible with an oxyhydrogen flame. The sealed crucible was placed in a swing furnace and degassed at low temperature for 12 hours. Then, the temperature was gradually increased to 1110℃ and held for 48 hours while periodically swinging to mix the melt. Subsequently, the melt was slowly cooled to room temperature with the furnace to obtain polycrystalline material of magnesium cadmium selenide (CdSelenium Selenide). The crucible containing the polycrystalline material was installed on a support of a three-temperature zone vertical Bridgman growth furnace. After 10 hours of heating, the high-temperature zone reached 1119℃, the medium-temperature zone reached 1070℃, and the low-temperature zone reached 750℃. The temperature was held for 12 hours to ensure that the raw material was completely melted. The crucible was lowered and rotated synchronously at a rate of 1 mm / h and the growth continued for 220 hours. The crystal started to grow from the bottom of the crucible. After the crystal growth was completed, the growth furnace was controlled to be cooled to 500℃ and in-situ annealed for 240 hours. The power was turned off and the crystal was allowed to cool to room temperature with the furnace to obtain single crystal of magnesium cadmium selenide (CdSelenium Selenide).

[0028] A Cd metal with a diameter of 30 mm and a length of 90 mm was successfully prepared using the above method. 0.95 Mg 0.05 Te 0.98 Se 0.02 Single crystal. IV testing shows that the resistivity can reach (See Figure 2 IR testing showed that the infrared transmittance could reach 66% (see...). Figure 3 Energy spectral response tests show that Cd 0.95 Mg 0.05 Te 0.98 Se 0.02 The room-temperature radiation detector fabricated from ingot-head crystals achieves an energy resolution of 13.21% (500V) at the optimal bias voltage (see...). Figure 4 Microhardness testing showed that Cd0.95 Mg 0.05 Te 0.98 Se 0.02 The crystal hardness is Hv = 0.53 GPa (see...) Figure 5 ).

[0029] Example 3 This embodiment prepares Cd with a Se content of 3 at%. 0.95 Mg 0.05 Te 0.97 Se 0.03 The specific steps for producing selenium-tellurium-magnesium-cadmium single crystals are as follows: Raw material loading: In the clean bench, according to Cd 0.95 Mg 0.05 Te 0.97 Se 0.03 According to stoichiometry, 141.76g, 1.70g, 177.92g and 3.69g of elemental raw materials of Cd, Mg, Te and Se (all with a purity of 7N) were accurately weighed. The above basic raw materials were placed into a 6N high-purity quartz crucible that had been acid-washed, dried and carbon-coated. 0.5at% of excess Te was added, and In dopant with a volume concentration of 10ppm and a purity of 7N was added. The crucible was gently shaken to reduce the porosity of the raw materials. Vacuum sealing: Place the quartz crucible filled with material into the vacuum sealing device, start the molecular pump to evacuate the vacuum until the vacuum level stabilizes at 6.0 × 10⁻⁶. -5 At Pa, the top of the crucible is sealed with an oxyhydrogen flame to ensure good airtightness of the crucible and prevent the volatilization of Se and Te elements at high temperature; High-temperature melting of the melt: The sealed crucible is placed in a swing furnace and degassed at 200℃ for 12 hours. Then, the temperature is increased to 1130℃ at a gradient heating rate of 93℃ / h and held for 48 hours. During the holding process, the crucible is periodically swinged at a frequency of 1.8r / min to ensure that the melt is fully convected and combined. Then, the power is turned off and the melt is cooled to room temperature with the furnace to obtain a polycrystalline material of selenium tellurium magnesium cadmium. Vertical Bridgman crystal growth: A crucible containing polycrystalline material is fixed on a support of a three-temperature zone crystal growth furnace. After sealing the furnace, the temperature is increased at a rate of 74℃ / h for 15 hours, so that the high-temperature zone reaches 1130℃, the medium-temperature zone reaches 1080℃, and the low-temperature zone reaches 780℃, forming a temperature gradient of 10K / cm. The temperature is held for 12 hours to completely melt the polycrystalline material. Then, the crucible is lowered at a rate of 0.8mm / h, and the crystal growth is completed in a directional manner for 180 hours. In-situ annealing: After crystal growth, the temperature was lowered to 500℃ at a rate of 10℃ / h for 200h in-situ annealing to eliminate internal thermal stress. After annealing, the power was turned off, and the crystal was cooled to room temperature in the furnace to obtain Cd. 0.95 Mg 0.05 Te0.97 Se 0.03 Selenium-tellurium-cadmium single crystal.

[0030] This embodiment successfully prepared a 30mm diameter, 95mm length magnesium cadmium selenide telluride single crystal. The crystal was macroscopically defect-free and had a uniform compositional distribution. Performance testing showed that the resistivity of this single crystal reached [value missing]. With an infrared transmittance of 64% and a microhardness of Hv=0.52GPa, the room temperature radiation detector made from it has an energy resolution of 16.55% under a bias voltage of 500V, and has excellent electrical, mechanical and radiation detection performance.

[0031] Example 4 This embodiment prepares Cd with a Se content of 4 at%. 0.95 Mg 0.05 Te 0.96 Se 0.04 The specific steps for producing selenium-tellurium-magnesium-cadmium single crystals are as follows: Raw material loading: In the clean bench, according to Cd 0.95 Mg 0.05 Te 0.96 Se 0.0 Stoichiometry was used to accurately weigh 140.30 g, 1.68 g, 176.00 g and 4.92 g of elemental raw materials of Cd, Mg, Te and Se (purity of Cd, Mg and Te is 5N, purity of Se is 7N) respectively. The raw materials were loaded into a treated 6N high-purity quartz crucible, and 0.5 at% excess Te was added. Then In dopant with a volume concentration of 10 ppm and purity of 7N was added. Vacuum sealing: Place the crucible in the vacuum sealing device and start the molecular pump to evacuate until the vacuum level stabilizes at 5.0 × 10⁻⁶. -5 Pa, the top of the crucible is sealed using an oxyhydrogen flame to ensure airtightness; High-temperature melting of the material: The sealed crucible is placed in a swing furnace and degassed at 200°C for 12 hours. Then, the temperature is increased to 1150°C at a gradient heating rate of 95°C / h and held for 48 hours. The crucible is then shaken at a frequency of 1.8 r / min to promote the mixing of the melt. The power is then turned off and the furnace is cooled to room temperature to obtain selenium tellurium magnesium cadmium polycrystalline material. Vertical Bridgman crystal growth: A crucible containing polycrystalline material is installed on a support of a three-temperature zone crystal growth furnace. After sealing the furnace, the temperature is increased at a rate of 56℃ / h for 20 hours, so that the high-temperature zone reaches 1140℃, the medium-temperature zone reaches 1090℃, and the low-temperature zone reaches 800℃, forming a temperature gradient of 15K / cm. The temperature is held for 12 hours to completely melt the polycrystalline material. Then, the crucible is lowered at a constant speed of 0.5mm / h while rotating at a rate of 4r / min. The crystal growth is completed in a directional manner for 110 hours. In-situ annealing: After crystal growth, the temperature was lowered to 500℃ at a rate of 10℃ / h for in-situ annealing for 180h to eliminate internal thermal stress; after annealing, the power was turned off and the furnace was cooled to room temperature to obtain Cd. 0.95 Mg 0.05 Te 0.96 Se 0.0 Selenium-tellurium-cadmium single crystal.

[0032] This embodiment successfully prepared a 30mm diameter, 85mm length magnesium cadmium selenide telluride single crystal. The crystal was free of macroscopic cracks and defects, and exhibited uniform axial and radial composition. Performance testing showed that the resistivity of this single crystal reached [value missing]. With an infrared transmittance of 62% and a microhardness of Hv=0.49GPa, the room temperature radiation detector made from it has an energy resolution of 18.03% under a bias voltage of 500V. All performance indicators are superior to those of low Se content selenium tellurium magnesium cadmium single crystal, making it a high-quality core material for high-performance room temperature radiation detectors.

Claims

1. A method for preparing a multi-component compound semiconductor crystal, characterized in that, The multi-component compound semiconductor crystal is a selenium-tellurium-cadmium crystal with the chemical formula Cd. 0.95 Mg 0.05 Te 1-x Se x The preparation method includes the following steps in sequence: high-temperature melting method for synthesizing selenium tellurium magnesium cadmium polycrystalline material, vertical Bridgman method for crystal growth, and in-situ annealing treatment. The raw materials for preparation contain Cd 0.95 Mg 0.05 Te 1-x Se x The basic raw materials of Cd, Mg, Te and Se are stoichiometrically proportioned, with an excess of Te added to the basic raw materials, and also doped with In. The crystal growth is carried out in a three-temperature zone crystal growth furnace. The high temperature zone of the three-temperature zone crystal growth furnace is 1110-1140℃, the medium temperature zone is 1060-1090℃, and the low temperature zone is 750-800℃. The crucible descent rate during the crystal growth process is 0.5-1mm / h.

2. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The Cd 0.95 Mg 0.05 Te 1-x Se x The atomic content of Se in the crystal is 0-4 at%, and the temperature gradient of the three-temperature zone crystal growth furnace is 10-15 K / cm.

3. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The excess Te has a molar fraction of 0.5%, and the In element doping volume concentration is 10 ppm.

4. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The process parameters for the high-temperature melting method are: vacuum degree (5-6) × 10 -5 Pa, melting temperature 1100-1150℃, holding time 48h.

5. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The purity of the Cd, Mg, Te, and Se raw materials is 5N-7N, the purity of the In element raw material is 7N, and the crucible used in the preparation is a 6N high-purity quartz crucible coated with a carbon film.

6. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The specific crystal growth process of the vertical Bridgman method is as follows: after heating to the set temperature in three temperature zones for 10-20 hours, the temperature is held for 12-16 hours to completely melt the polycrystalline material. The crucible is lowered and rotated synchronously. The total crystal growth time is 110-220 hours.

7. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The process parameters for the in-situ annealing treatment are: annealing temperature 500℃, annealing time 120-240h, after annealing, the power supply of the growth furnace is turned off, and the crystal is cooled to room temperature with the furnace.

8. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The specific steps for synthesizing polycrystalline materials using the high-temperature melting method are as follows: After loading all the proportioned raw materials into the quartz crucible, a molecular pump is used to evacuate to the set vacuum level, and the quartz crucible is then melt-sealed. The sealed crucible is placed in a gyratory furnace, degassed at a low temperature for 12-16 hours, then gradually heated to the melting temperature, held at the temperature and periodically gyrated to promote melt convection, and finally cooled to room temperature with the furnace to obtain polycrystalline material.

9. The method for preparing a multi-component compound semiconductor crystal according to claim 1, characterized in that, The crystal is a single crystal of magnesium cadmium selenide telluride, with a crystal diameter of not less than 30 mm and a resistivity of not less than [missing value]. The microhardness is not less than 0.41 GPa, and the infrared transmittance is not less than 60%.

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