Growth method of selenium-germanium-mercury-barium single crystal

Abstract

The invention discloses a selenium-germanium-mercury-barium single crystal growth method which comprises the following steps: a crucible containing selenium-germanium-mercury-barium polycrystals is placed in a quartz tube, the quartz tube is vacuumized and then placed in a single crystal growth furnace, and the single crystal growth furnace comprises a high-temperature area, a gradient area and a low-temperature area which are sequentially and continuously arranged from top to bottom; adjusting the temperature in the single crystal growth furnace until the temperature of a high-temperature zone is 730-760 DEG C, the temperature of a low-temperature zone is 560-590 DEG C, and the temperature of a gradient zone is reduced from the temperature of the high-temperature zone to the temperature of the low-temperature zone according to the temperature gradient of 8-12 DEG C / cm; a seed-crystal-free spontaneous nucleation method is adopted to grow the crystal; and after crystal growth is finished, cooling to room temperature. The growth method of the selenium-germanium-mercury-barium single crystal well solves the problems that the non-stoichiometric ratio and the yield of selenium-germanium-mercury-barium polycrystal synthesis are low, invalid crystal nucleuses are easily formed in the spontaneous nucleation stage of selenium-germanium-mercury-barium, the crystal quality is unstable and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance nonlinear optical crystals. More specifically, it relates to a method for growing barium mercury germanium selenide single crystals. Background Art

[0002] All-solid-state lasers with infrared nonlinear optical crystals as the key core components can generate mid-infrared and far-infrared lasers in the 3-17 μm band through frequency conversion under near-infrared laser pumping, and thus have extensive applications in fields such as environmental monitoring, medical surgery, lidar, and scientific research. Barium mercury germanium selenide, with the molecular formula BaHgGeSe4, is a new type of infrared nonlinear optical crystal with excellent performance. It has a large nonlinear optical effect (d 24 = 31.7 pm / V), high transmittance in the mid-infrared and far-infrared ranges, large birefringence, and a high laser damage threshold, and thus has important application value.

[0003] Currently, the method for synthesizing barium mercury germanium selenide polycrystalline raw materials is the atmospheric pressure single-temperature zone method, that is, a constant temperature zone is set, and high-purity elemental raw materials are used for high-temperature reaction synthesis in a quartz tube at a temperature above 750 °C. At this temperature, the vapor pressure of selenium is very high, and in addition, the active metal barium corrodes the quartz tube, so the quartz tube often cracks. In addition, volatile HgSe and GeSe2 impurity phases are easily generated during this reaction process, resulting in component deviation and low yield, and the obtained polycrystals cannot meet the requirements for further single crystal growth.

[0004] Barium mercury germanium selenide crystals mainly grow by spontaneous nucleation without a seed crystal. In order to ensure obtaining large crystal nuclei using the geometric elimination mechanism, a crucible with a fine conical front end needs to be used. However, this crucible is not easy to clean, is prone to introducing foreign impurities to form ineffective crystal nuclei, and the crystal growth direction is uncertain, bringing great difficulties to crystal orientation and processing. On the other hand, the support rods used in traditional crystal growth only contact the quartz crucible at the edge, and cannot timely conduct the excess latent heat in the growing crystal. During the cooling process of the crystal, cracks often occur due to excessive thermal stress; moreover, traditional support rods cannot effectively weaken the air convection in the furnace, and the temperature field in the furnace has large fluctuations during crystal growth, seriously affecting crystal quality. Summary of the Invention

[0005] Based on the above facts, an object of the present invention is to provide a method for growing barium mercury germanium selenide single crystals. This method for growing barium mercury germanium selenide single crystals well solves the problems of non-stoichiometry and low yield in the synthesis of barium mercury germanium selenide polycrystals, easy formation of ineffective crystal nuclei in the spontaneous nucleation stage of barium mercury germanium selenide, and unstable crystal quality.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for growing a selenium-germanium-mercury-barium single crystal, comprising the following steps:

[0008] Place the crucible containing the selenium-germanium-mercury-barium polycrystal in a quartz tube, evacuate the quartz tube and then place it in a single crystal growth furnace, wherein the single crystal growth furnace includes a high-temperature zone, a gradient zone, and a low-temperature zone that are continuously arranged from top to bottom;

[0009] Adjust the temperature in the single crystal growth furnace so that the temperature in the high-temperature zone is 730 - 760 °C, the temperature in the low-temperature zone is 560 - 590 °C, and the temperature in the gradient zone decreases from the temperature in the high-temperature zone to the temperature in the low-temperature zone at a temperature gradient of 8 - 12 °C / cm;

[0010] Grow the crystal by the seedless spontaneous nucleation method;

[0011] After the crystal growth is completed, cool down to room temperature.

[0012] In this single crystal growth furnace, the high-temperature zone, the gradient zone, and the low-temperature zone are continuously arranged. That is, the starting position of the gradient zone is the ending position of the high-temperature zone, and the temperature at the starting position of the gradient zone is the same as the temperature in the high-temperature zone; the ending position of the gradient zone is the starting position of the low-temperature zone, and the ending temperature of the gradient zone is the same as the temperature in the low-temperature zone.

[0013] Further, the single crystal growth furnace is preferably a vertical three-zone Bridgman growth furnace. The vertical three-zone Bridgman furnace includes the high-temperature zone, the gradient zone, and the low-temperature zone from top to bottom in sequence.

[0014] Further, the crucible is a PBN crucible.

[0015] Further, both the crucible and the quartz tube are soaked in aqua regia, cleaned, dried, and then used.

[0016] Further, the crucible is a PBN crucible. A seed crystal pocket is provided at the bottom of the crucible.

[0017] Further, the vacuum degree in the quartz tube is 10 -4 -10 -6 Pa, and the sealing method is preferably sealing with a hydrogen-oxygen flame.

[0018] Further, before crystal growth, the bottom end of the seed crystal pocket at the bottom of the crucible is located at the starting position of the gradient zone.

[0019] Further, the method for adjusting the temperature of the single crystal growth furnace includes the following steps:

[0020] Raise the temperature in the high-temperature zone to 800 - 850 °C, raise the temperature in the low-temperature zone to 650 - 700 °C, and keep it at this temperature for 18 - 24 h;

[0021] Reduce the temperature of the high-temperature zone by 80 - 100 °C and the temperature of the low-temperature zone by 100 - 120 °C, and hold at this temperature for 3 - 5 h;

[0022] Raise the temperature of the high-temperature zone to 730 - 760 °C and the temperature of the low-temperature zone to 560 - 590 °C, and hold at this temperature for 10 - 15 h;

[0023] Among them, during the process of adjusting the temperature of the single crystal growth furnace, the temperature in the gradient zone decreases from the corresponding high-temperature zone temperature to the corresponding low-temperature zone temperature at a temperature gradient of 8 - 12 °C / cm.

[0024] During the single crystal growth process, the temperature of the melt after melting the materials is about 10 - 50 °C higher than the melting point temperature. Holding at this high-temperature zone temperature for 18 - 24 hours can ensure that all solute particles are heated evenly and melted sufficiently; due to the special thermal properties of mercury barium selenide germanium, the difference between its melting point and freezing point is 140 °C. Therefore, by slowly cooling, the temperature of the high-temperature zone is reduced by 80 - 100 °C, while the temperature of the low-temperature zone is reduced by 100 - 120 °C and held for 3 - 5 h. This process enables the melt in the seed crystal bag to form small crystal nuclei through rapid cooling crystallization; the final heating process will melt away the ineffective small crystal nuclei formed during the cooling process, leaving slightly larger grains, and finally a large single crystal with stable quality is obtained through the geometric elimination mechanism.

[0025] The growth crucible used in this method is preferably a PBN growth crucible with a seed crystal bag. This crucible has a cylindrical seed crystal bag front end with a smaller inner diameter, which is beneficial to the geometric elimination mechanism and is also easy to clean.

[0026] Further, the method for growing a crystal includes the following steps:

[0027] At a speed of 0.1 - 1 mm / h, make the materials in the quartz tube start from the starting position of the gradient zone, pass through the gradient zone and the low-temperature zone in sequence, and rotate the quartz tube horizontally at the same time for crystal growth.

[0028] In this method for growing a crystal, the method of making the materials pass through the gradient zone and the low-temperature zone in sequence includes but is not limited to: relative to the quartz tube, raising the furnace body of the single crystal growth furnace at a speed of 0.1 - 1 mm / h. Moving the furnace body during crystal growth is beneficial to maintaining the stability of the solid-liquid interface, reducing the point defect concentration and dislocation density. The crystal direction grown using this crucible is determined, the crystal is more regular, easy to cut, and the crystal utilization rate is high.

[0029] Further, the method for horizontally rotating the quartz tube is as follows: Rotate the quartz tube according to a trapezoidal wave. The forward acceleration time of this trapezoidal wave is 10 - 15 s, the constant time is 60 - 80 s, and the rotation speed is 10 - 15 revolutions per minute; the reverse acceleration time is 10 - 15 s, the constant time is 60 - 80 s, and the rotation speed is 10 - 15 revolutions per minute. By controlling the conditions for horizontally rotating the quartz tube, it is beneficial to obtain a high-yield and stable-quality mercury barium selenium germanium single crystal.

[0030] Further, the speed at which the material in the quartz tube passes through the gradient region and the low temperature region is 0.5 mm / h.

[0031] Further, after the quartz tube is placed in the support rod, it is then placed in a single crystal growth furnace; among them, the structure of the support rod includes:

[0032] A columnar hollow support part; and

[0033] A frustum-shaped hollow support part located at one end of the columnar hollow support part;

[0034] Among them, the columnar hollow support part and the frustum-shaped hollow support part are concentric hollow structures. The hollow structure is a hollow columnar structure.

[0035] Further, the quartz tube is placed in the hollow of the support rod.

[0036] Further, the material of the support rod is quartz.

[0037] The use of this support rod has at least three advantages: First, the side cone of the frustum can be used to weaken the air convection in the furnace body, avoid large fluctuations in the temperature field during crystal growth, and keep the growth process stable; second, the quartz support rod can be used to timely export the excess latent heat in the growing crystal, avoiding crystal cracking due to excessive thermal stress during the cooling process; third, since the quartz crucible and the quartz support rod are made of the same material and have the same coefficient of thermal expansion, similar to the situation when using a corundum support rod, the support rod will not crack during the cooling process, providing safety guarantee for the crystal growth process.

[0038] Further, the preparation of the mercury barium selenium germanium polycrystal includes the following steps:

[0039] After mixing and grinding the mixture of binary selenide raw materials BaSe, HgSe, and GeSe2 with elemental Se, the obtained material is vacuum-sealed and then heated to 650 - 700 °C in an inert atmosphere and held for 30 - 50 h; then heated by 50 - 70 °C and held for 100 - 120 h to mix the material evenly; cooled to room temperature at a speed of 10 - 20 °C / h to obtain the mercury barium selenium germanium polycrystal.

[0040] Further, the molar ratio of BaSe, HgSe, and GeSe2 is 1:1:1.

[0041] Further, the mass of the elemental Se is 0.5 - 1.5 wt% of the mass of the mixture.

[0042] Further, the heating rate for heating to 650 - 700 °C is 60 - 80 °C / h.

[0043] Further, the preparation of the barium mercury germanium selenide polycrystal includes the following steps:

[0044] Mix the mixture of the binary selenide raw materials BaSe, HgSe, and GeSe2 with elemental Se, grind them, place them in a quartz tube, evacuate the quartz tube and seal it, and then place it in a polycrystalline growth furnace;

[0045] Fill the polycrystalline growth furnace with argon at 10 - 15 atm, heat the temperature in the furnace to 650 - 700 °C, and keep it warm for 30 - 50 h; then heat it at a rate of 100 - 130 °C / h for 50 - 70 °C and keep it warm for 100 - 120 h to mix the materials evenly; cool it to room temperature at a rate of 10 - 20 °C / h to obtain the barium mercury germanium selenide polycrystal.

[0046] In the preparation of the barium mercury germanium selenide polycrystal, the quartz tube is preferably soaked in aqua regia first, then cleaned and dried before use.

[0047] Further, in the preparation of the barium mercury germanium selenide polycrystal, the vacuum degree of the evacuated quartz tube is 10 -4 -10 -6 Pa. The sealing method is preferably sealing with a hydrogen-oxygen flame.

[0048] Further, the method of mixing the materials evenly is to shake the furnace body of the polycrystalline growth furnace to shake the quartz tube. The shaking rate of the furnace body is preferably 30 - 50 times per hour.

[0049] In the preparation process of the polycrystal, reacting the three binary selenide raw materials BaSe, HgSe, and GeSe2 in a quartz tube can avoid the corrosion of the quartz tube by the active metal barium; adding a certain amount of elemental Se in the quartz tube can effectively inhibit the volatilization of HgSe and GeSe2, the product composition conforms to the stoichiometric ratio, and the yield is increased; filling the polycrystalline growth furnace (preferably a high-pressure reaction furnace) with argon can balance the vapor pressure generated by Se at high temperatures and prevent the quartz tube from bursting; shaking the quartz tube during the reaction process can make the high-temperature melt in the tube fully contact, the reaction is sufficient, and the generation of heterophase is avoided.

[0050] The beneficial effects of the present invention are as follows:

[0051] In the method for growing barium mercury germanium selenide single crystal provided by the present invention, by controlling the growth conditions of barium mercury germanium selenide polycrystal and barium mercury germanium selenide single crystal, the obtained barium mercury germanium selenide single crystal has stable quality, high yield, and the growth method has good stability and high repeatability. Description of the Drawings

[0052] The following further elaborates on the specific embodiments of the present invention in conjunction with the drawings.

[0053] Figure 1 The structural schematic diagram of the support rod in the embodiment is shown.

[0054] Figure 2 The XRD spectrum of the barium mercury germanium selenide single crystal in Example 3 is shown. Specific Embodiments

[0055] To more clearly illustrate the present invention, the following further describes the present invention in conjunction with preferred embodiments and the drawings. Similar components in the drawings are denoted by the same reference numerals. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0056] Example 1

[0057] The synthesis of barium mercury germanium selenide polycrystal includes the following steps:

[0058] Mix barium selenide BaSe, mercury selenide HgSe, and germanium diselenide GeSe2 according to the molar ratio of BaSe:HgSe:GeSe2 = 1:1:1 to obtain a mixture, and weigh elemental selenium Se at 0.5 wt% of the mass content of the mixture;

[0059] Specifically, during the batching process, the addition amounts of each component are: 54.073 grams of barium selenide, 69.888 grams of mercury selenide, 57.640 grams of germanium diselenide, and 0.908 grams of elemental selenium;

[0060] The synthesis process steps are as follows:

[0061] 1) Cleaning and drying of the reaction vessel

[0062] Wet-rinse the quartz tube with tap water, soak it in aqua regia for 24 hours, then rinse it with tap water until neutral, place it in an ultrasonic cleaning tank and oscillate and clean for 30 minutes, repeatedly rinse it with deionized water until clean, then clean it with high-purity alcohol, and put it in an oven at 100 °C for drying and standby;

[0063] 2) Loading

[0064] Fully grind the weighed barium selenide, mercury selenide, germanium diselenide, and elemental selenium and load them into the quartz tube. After loading, evacuate to 10 -4Pa, seal the quartz tube with a hydrogen-oxygen flame;

[0065] 3) Synthesis

[0066] Put the above-mentioned quartz tube filled with raw materials and sealed into a horizontal high-temperature and high-pressure synthesis furnace. Before heating up, first fill the inside of the furnace chamber with 10 atm of argon. This horizontal high-temperature and high-pressure synthesis furnace is a single-temperature zone resistance furnace; first, the temperature of this temperature zone is raised to 650 °C at a rate of 1 °C per minute and kept warm for 30 hours. During this stage, the reaction raw materials undergo a solid-phase transfer process; then the temperature of this temperature zone is raised to 700 °C at a rate of 2 °C per minute and kept warm for 100 hours; during this heat preservation process, the unilateral lifting device of the high-pressure furnace is lifted up and down, and the quartz tube is shaken to make the melt fully homogenized. The shaking rate of the furnace body is 30 times per hour; finally, the temperature of the entire resistance furnace is lowered to room temperature at a rate of 10 °C per hour to obtain mercury barium germanium selenide polycrystal.

[0067] In this example, 180 grams of high-purity, single-phase mercury barium germanium selenide polycrystal raw materials are obtained, and the yield is greater than 99%.

[0068] After repeating this polycrystal growth method 5 times, the obtained results are basically the same.

[0069] Example 2

[0070] The synthesis of mercury barium germanium selenide polycrystal includes the following steps:

[0071] Mix barium selenide BaSe, mercury selenide HgSe, and germanium diselenide GeSe2 according to the molar ratio of BaSe:HgSe:GeSe2 = 1:1:1 to obtain a mixture, and weigh elemental selenium Se material according to 1.5 wt% of the mass content of this mixture;

[0072] Specifically, during the batching process, the addition amounts of each component are: 81.110 grams of barium selenide, 104.832 grams of mercury selenide, 86.46 grams of germanium diselenide, and 4.056 grams of selenium;

[0073] The synthesis process steps are as follows:

[0074] 1) Cleaning and drying of the reaction vessel

[0075] Wet and rinse the quartz tube with tap water, soak it in aqua regia for 24 hours, then rinse it with tap water until neutral, place it in an ultrasonic cleaning tank and oscillate and clean for 30 minutes, repeatedly rinse it with deionized water until clean, then clean it with high-purity alcohol, and put it in an oven at 100 °C to dry for later use;

[0076] 2) Loading materials

[0077] Fully grind the weighed barium selenide, mercury selenide, germanium diselenide, and elemental selenium and load them into the quartz tube. After loading, evacuate to 10 -4Pa, seal the quartz tube with a hydrogen-oxygen flame;

[0078] 3) Synthesis

[0079] Put the above quartz tube filled with raw materials and sealed into a horizontal high-temperature and high-pressure synthesis furnace, which is a single-temperature-zone resistance furnace. Before heating up the horizontal high-temperature and high-pressure synthesis furnace, first fill the inside of the furnace chamber with 15 atm of argon gas. First, the temperature of this temperature zone is raised to 700 °C at a rate of 1 °C per minute and kept warm for 50 hours. During this stage, the reaction raw materials undergo a solid-phase transfer process; then the temperature of this temperature zone is raised to 770 °C at a rate of 2 °C per minute and kept warm for 120 hours; during this insulation process, the unilateral lifting device of the high-pressure furnace is lifted up and down, and the quartz tube is shaken to make the melt fully homogenized. The shaking rate of the furnace body is 50 times per hour; finally, the temperature of the entire resistance furnace is lowered to room temperature at a speed of 10 °C per hour to obtain HgBaGeSe polycrystal.

[0080] In this example, 270 grams of high-purity, single-phase HgBaGeSe polycrystalline raw materials are obtained, and the yield is greater than 99%.

[0081] After repeating this polycrystal growth method 5 times, the obtained results are basically the same.

[0082] Example 3

[0083] Growth of HgBaGeSe single crystal:

[0084] The single crystal growth method of HgBaGeSe in this example includes the following steps:

[0085] 1) Soak the PBN crucible and quartz tube for crystal growth with aqua regia, then wash with ultrapure water and dry; among them, the single crystal growth PBN crucible is cylindrical with a seed crystal bag. The length of the PBN crucible is 200 mm, the inner diameter is 30 mm, and the inner diameter of the seed crystal well at the front end is 2 mm and the length is 30 mm;

[0086] 2) Then add 180 grams of the HgBaGeSe polycrystal prepared in Example 1 to the crucible, then place the crucible vertically in the quartz tube, evacuate the quartz tube to 10 -4 Pa, and finally seal the quartz tube with a hydrogen-oxygen flame;

[0087] 3) Place the sealed quartz tube in the support rod (where the structure of the support rod is as Figure 1 shown, and the structure includes a columnar hollow support part 1 and a frustum-shaped hollow support part 2 located at one end of the columnar hollow support part 1; among them, the columnar hollow support part 1 and the frustum-shaped hollow support part 2 are concentric hollow cylindrical structures 3), and then put it into a vertical double-temperature-zone tube resistance furnace. The growth furnace from top to bottom is a high-temperature zone, a gradient zone, and a low-temperature zone. The length of the high-temperature zone is 200 mm, the length of the gradient zone is 100 mm, and the length of the low-temperature zone is 300 mm. The bottom end of the seed crystal is located at the starting position of the gradient zone;

[0088] 4) First, raise the temperature of the high-temperature zone to 800 °C, while raising the temperature of the low-temperature zone to 700 °C. The temperature gradient in the gradient zone is 8 °C / cm, and keep it for 18 h. This is the first stage. Then, lower the temperature of the high-temperature zone by 80 °C, while lowering the temperature of the low-temperature zone by 120 °C, and keep it for 3 h. This is the second stage. Then, raise the temperature of the high-temperature zone by 10 °C, while raising the temperature of the low-temperature zone by 10 °C, and keep it for 10 h. This is the third stage.

[0089] 5) Keep the quartz tube stationary, and keep the temperatures of the high-temperature and low-temperature zones of the furnace body unchanged. Then, move the furnace body upward at a rate of 0.1 mm / h to move the low-temperature zone upward. At the same time, rotate the quartz tube with a trapezoidal wave. The forward acceleration time is 10 s, the constant time is 60 s, the rotation speed is 10 revolutions per minute, the reverse acceleration time is 10 s, the constant time is 60 s, and the rotation speed is 10 revolutions per minute. The temperature of the molten material decreases slowly and crystallizes to grow crystals. After the growth is completed, lower the temperature of the entire resistance furnace to room temperature at a rate of 10 °C / h to obtain a mercury barium selenium germanium single crystal. Its XRD pattern is as Figure 2 shown.

[0090] The mercury barium selenium germanium single crystal prepared in this example has a diameter of 30 mm and a length of 100 mm. The crystal is regular, with few defects, has a high transmittance in the 1-14 μm band, and is easy to be processed directionally, and the crystal utilization rate is high.

[0091] After repeating this single crystal growth method 10 times, the obtained results are basically the same.

[0092] Example 4

[0093] Growth of mercury barium selenium germanium single crystal:

[0094] The single crystal growth method of mercury barium selenium germanium in this example includes the following steps:

[0095] 1) Soak the PBN crucible and quartz tube for crystal growth with aqua regia, then wash with ultrapure water and dry. The PBN crucible for single crystal growth is cylindrical with a seed crystal bag. The length of the PBN crucible is 200 mm, the inner diameter is 20 mm, and the inner diameter of the seed crystal well at the front end is 2 mm and the length is 30 mm.

[0096] 2) Then, add 270 g of the mercury barium selenium germanium polycrystal of Example 2 into the crucible, then place the crucible vertically in the quartz tube, evacuate the quartz tube to 10 -4 Pa, and finally seal the quartz tube with a hydrogen-oxygen flame.

[0097] 3) Place the sealed quartz tube in the support rod (where the structure of the support rod is as Figure 1As shown, the structure includes a columnar hollow support portion 1; and a frustum-shaped hollow support portion 2 located at one end of the columnar hollow support portion 1; wherein, the columnar hollow support portion 1 and the frustum-shaped hollow support portion 2 are concentric hollow cylindrical structures 3. Then, it is placed in a vertical double-temperature zone tube resistance furnace. The growth furnace has a high-temperature zone, a gradient zone, and a low-temperature zone from top to bottom. The length of the high-temperature zone is 200 mm, the length of the gradient zone is 100 mm, and the length of the low-temperature zone is 300 mm. The bottom end of the seed crystal is located at the starting position of the gradient zone;

[0098] 4) First, raise the temperature of the high-temperature zone to 850 °C, and at the same time raise the temperature of the low-temperature zone to 650 °C. The temperature gradient of the gradient zone is 12 °C / cm, and keep it warm for 24 h. This is the first stage; then lower the temperature of the high-temperature zone by 100 °C, and at the same time lower the temperature of the low-temperature zone by 100 °C, and keep it for 5 h. This is the second stage; then raise the temperature of the high-temperature zone by 10 °C, and at the same time raise the temperature of the low-temperature zone by 10 °C, and keep it for 15 h. This is the third stage;

[0099] 5) Keep the quartz tube stationary, and keep the temperatures of the high-temperature zone and the low-temperature zone of the furnace body unchanged. Then move the furnace body upward at a rate of 1 mm / h to move the low-temperature zone upward. At the same time, rotate the quartz tube with a trapezoidal wave. The forward acceleration time is 15 s, the constant time is 80 s, the rotation speed is 15 revolutions per minute, the reverse acceleration time is 15 s, the constant time is 80 s, and the rotation speed is 15 revolutions per minute; the temperature of the melted material decreases slowly and crystallizes to carry out crystal growth; after the growth is completed, lower the temperature of the entire resistance furnace to room temperature at a rate of 10 °C / h to obtain a mercury barium selenium germanium single crystal.

[0100] The mercury barium selenium germanium single crystal prepared in this example has a diameter of 20 mm and a length of 120 mm. The crystal is regular, has few defects, has a high transmittance in the 1-14 μm band, and is easy to be directionally processed with a high crystal utilization rate.

[0101] After repeating this single crystal growth method 10 times, the obtained results are basically the same.

[0102] Comparative Example 1

[0103] Repeat Example 3, with the difference that the support rod is in a hollow cylindrical shape and other conditions remain unchanged. Obvious twin crystals appear in the shoulder part of the crystal.

[0104] Comparative Example 2

[0105] Repeat Example 3, with the difference that during the growth process of the mercury barium selenium germanium single crystal, in step 4), directly set the temperature of the high-temperature zone to 730 °C, and at the same time raise the temperature of the low-temperature zone to 590 °C. The temperature gradient of the gradient zone is 8 °C / cm, and keep it warm for 31 h. With other conditions unchanged, there are voids inside the obtained crystal and it does not completely crystallize to form a complete crystal.

[0106] Comparative Example 3

[0107] Repeat Example 3, except that during the growth process of the mercury barium germanium selenide single crystal, in step 5), when rotating the quartz tube with a trapezoidal wave, the forward acceleration time is 8 s, the constant time is 62 s, the rotation speed is 15 revolutions / min, the reverse acceleration time is 8 s, the constant time is 62 s, and the rotation speed is 15 revolutions / min. With other conditions unchanged, many defects are formed inside the obtained crystal due to poor melt uniformity, and the quality is poor.

[0108] Comparative Example 4

[0109] Repeat Example 3, except that during the growth process of the mercury barium germanium selenide single crystal, the rate of moving the furnace body upward is 1.2 mm / h. With other conditions unchanged, since the crystal cooling rate is too fast, the crystallization process is not completed, and the obtained crystal is in a polycrystalline state.

[0110] Comparative Example 5

[0111] Repeat Example 3, except that during the growth process of the mercury barium germanium selenide single crystal, the rate of moving the furnace body upward is 0.08 mm / h. With other conditions unchanged, since the crystal cooling rate is too slow, the volatilization is serious, and there are mosaic crystals formed.

[0112] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for growing a mercury barium germanium selenide single crystal, characterized in that, It includes the following steps: Place the crucible containing selenium-germanium-mercury-barium polycrystal in a quartz tube. After evacuating the quartz tube, place it in a single crystal growth furnace. Among them, the single crystal growth furnace includes a high-temperature zone, a gradient zone, and a low-temperature zone that are continuously arranged from top to bottom in sequence; Adjust the temperature in the single crystal growth furnace until the temperature in the high-temperature zone is 730 - 760 °C, the temperature in the low-temperature zone is 560 - 590 °C, and the temperature in the gradient zone decreases from the temperature in the high-temperature zone to the temperature in the low-temperature zone at a temperature gradient of 8 - 12 °C / cm; Grow crystals by the spontaneous nucleation method without a seed crystal; After the crystal growth is completed, cool down to room temperature.

2. The growth method according to claim 1, wherein The method for adjusting the temperature of the single crystal growth furnace includes the following steps: Raise the temperature in the high-temperature zone to 800 - 850 °C and the temperature in the low-temperature zone to 650 - 700 °C, and keep the temperature for 18 - 24 h at this temperature; Lower the temperature in the high-temperature zone by 80 - 100 °C and the temperature in the low-temperature zone by 100 - 120 °C, and keep the temperature for 3 - 5 h at this temperature; Raise the temperature in the high-temperature zone to 730 - 760 °C and the temperature in the low-temperature zone to 560 - 590 °C, and keep the temperature for 10 - 15 h at this temperature; Among them, during the process of adjusting the temperature of the single crystal growth furnace, the temperature in the gradient zone decreases from the corresponding high-temperature zone temperature to the corresponding low-temperature zone temperature at a temperature gradient of 8 - 12 °C / cm.

3. The growth method according to claim 1, wherein The method for growing crystals includes the following steps: At a speed of 0.1 - 1 mm / h, make the material in the quartz tube start from the starting position of the gradient zone, pass through the gradient zone and the low-temperature zone in sequence, and at the same time horizontally rotate the quartz tube to carry out crystal growth.

4. The growth method according to claim 3, characterized in that, The method for horizontally rotating the quartz tube is: rotate the quartz tube according to a trapezoidal wave. The forward acceleration time of this trapezoidal wave is 10 - 15 s, the constant time is 60 - 80 s, and the rotation speed is 10 - 15 revolutions per minute; the reverse acceleration time is 10 - 15 s, the constant time is 60 - 80 s, and the rotation speed is 10 - 15 revolutions per minute.

5. The growth method according to claim 3, characterized in that, The speed at which the material in the quartz tube passes through the gradient zone and the low-temperature zone in sequence is 0.5 mm / h.

6. The growth method according to any one of claims 1-5, characterized in that, After the quartz tube is placed in the support rod, then place it in the single crystal growth furnace; among them, the structure of the support rod includes: A columnar hollow support part; and A frustum-shaped hollow support part located at one end of the columnar hollow support part; Among them, the columnar hollow support part and the frustum-shaped hollow support part are concentric hollow structures.

7. The growth method according to claim 6, characterized in that, The quartz tube is placed in the hollow of the support rod.

8. The growth method according to claim 1, wherein The preparation of the selenium-germanium-mercury-barium polycrystal includes the following steps: Mix the mixture of binary selenide raw materials BaSe, HgSe, and GeSe2 with elemental Se, grind the obtained material, vacuum seal it, and then under an inert atmosphere, raise the temperature to 650 - 700 °C and keep the temperature for 30 - 50 h; then raise the temperature at a rate of 100 - 130 °C / h for 50 - 70 °C and keep the temperature for 100 - 120 h to mix the material evenly; lower the temperature to room temperature at a speed of 10 - 20 °C / h to obtain the selenium-germanium-mercury-barium polycrystal.

9. The growth method according to claim 8, characterized in that, The molar ratio of BaSe, HgSe, and GeSe2 is 1:1:1; and / or The mass of the elemental Se is 0.5 - 1.5 wt% of the mass of the mixture.

10. The growth method according to claim 8, characterized in that, The heating rate for heating to 650 - 700 °C is 60 - 80 °C / h.

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