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Improved temperature gradient method for BaY2F8 monocrystal growing and device therefor

A technology of temperature gradient method and growth device, which is applied in the direction of single crystal growth, crystal growth, single crystal growth, etc., can solve the problems of low growth rate, small size, difficulty in shouldering, etc., and achieve convenient growth process and good crystal quality , easy to automatically control the effect

Inactive Publication Date: 2008-10-01
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to BaY near the melting point 2 f 8 The melt is viscous, the fluidity is poor, and the convection effect is not obvious. In addition, when the vacuum degree is insufficient, the impurities formed by the fluoride are easily oxidized and float on the surface of the melt. Cold, difficult to shoulder, difficult to grow high-quality, large-sized single crystals
In recent years, the pulling method has been used to grow BaY in domestic literature 2 f 8 Single crystal reports, but there are problems such as low growth rate and small size
From BaY 2 f 8 In view of the habit of crystallization, the pulling method growth is not the most effective method

Method used

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  • Improved temperature gradient method for BaY2F8 monocrystal growing and device therefor
  • Improved temperature gradient method for BaY2F8 monocrystal growing and device therefor
  • Improved temperature gradient method for BaY2F8 monocrystal growing and device therefor

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Experimental program
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Effect test

Embodiment 1

[0021] Embodiment 1, the unique design of small cone angle crucible

[0022] Crucible design such as figure 1 shown. The bottom of the crucible is a seeding capillary with a diameter of 2 mm. A capillary with such a scale diameter is conducive to the selection of a single growth direction in the spontaneous crystallization process of the crystal. If the diameter is too small, the generated surface tension will make it difficult for the melt to enter the capillary. In this example, the length of the seeding capillary is 30mm. The middle part of the crucible (the shoulder part) is an inverted conical shape, and its characteristic is that the apex angle of the cone is a small angle, about 29°. This is different from other crystals (such as CaF 2 , NaF and other crystals) The cone angle of the shoulder part of the crucible used in the temperature gradient method growth. Relevant theoretical calculations show that the angle of the apex angle of the cone designed here complies ...

Embodiment 2

[0027] Embodiment 2, temperature gradient and test

[0028] The appropriate temperature gradient is the temperature gradient method to grow BaY 2 f 8 One of the key elements of the crystal. Figure 2 It is a schematic structural diagram of a single crystal growth device in the method of the present invention. Vacuum tungsten rod resistance heating is used, the crucible is placed in the middle of the heating element, and the heating element is surrounded by multi-layer concentric molybdenum-skinned drums for heat preservation. The base is made of stainless steel, and a ring-shaped alumina ceramic plate is placed above the base. There is a gap of not less than 2cm between the ring-shaped ceramic plate and the crucible holder.

[0029] The top opening of the molybdenum skin insulation barrel and the center of the alumina ceramic plate leave a gap, which is one of the characteristics of the present invention, and its purpose is to help form a larger and longer distance axial t...

Embodiment 3

[0030] Embodiment 3, doping Er 3+ The heavy metal fluoride BaY 2 f 8 Temperature Gradient Growth of Single Crystal

[0031] 1. Prepare the high-purity BaF 2 , YF 3 Weigh according to the molar ratio of 1:2, and add 2mol.% of ErF 3 , grind and mix evenly in an agate mortar, and dry for later use.

[0032] 2. Furnace loading Put the prepared raw materials into the graphite crucible with small cone angle.

[0033] 3. Vacuumize the furnace until the air pressure in the furnace is lower than 5×10 -3 Pa, filled with high-purity argon as a protective gas.

[0034] 4. Heat the molten material to 1200°C and keep it at this temperature for 2 hours to ensure that the raw materials are completely melted and mixed evenly.

[0035]5. The temperature is lowered using the FP93 automatic temperature controller produced by SHIMADEN, and the temperature is uniformly lowered at a rate of 4° C. / hour for crystal growth. Since the pre-adjusted temperature gradient in the furnace is 8° C. / mm...

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Abstract

An improved temperature gradient method suitable for BaY2F8 monocrystal generation and a small cone angle pot used by the method and improvement of related monocrystal generation are provided. The small cone angle pot provided by the invention is made of highly pure graphite. A shoulder part in the middle of the pot is in conversed cone-shape. A vertex angle of the cone is 25 degrees to 35 degrees. The monocrystal generation device comprises a small cone angle said and other improved related devices. Other related devices are mainly improved in that a gap that is no less than 2cm is left between a top opening of the molybdenum layer heat preservation cylinder, an alumina ceramic plate and a molybdenum-made pot. The keys of the improved temperature gradient method that generates BaY2F8 monocrystal lie in that under axial temperature gradientno less than 6 deg C / mm, reducing temperature and generating the crystal at temperature reduction speed that enables the generation speed not higher than 1.8mm / h. The method of the invention is also suitable for generation of doped BaY2F8 of various types.

Description

【Technical field】: [0001] The invention belongs to the technical field of optoelectronic information materials, in particular to a heavy metal fluoride BaY 2 f 8 Single crystal and doped BaY 2 f 8 The temperature gradient method of single crystal growth and its small conical angle crucible and the improvement of the single crystal growth device. 【Background technique】: [0002] The methods for growing crystals from the melt mainly include pulling method, crucible descent method, temperature gradient method (in the present invention or simply referred to as temperature gradient method), flame melting method, zone melting method and laser pedestal method, etc., wherein the pulling method ( Also known as Czochralski method) is the most widely used, and its founder is J.Czochralski. On the other hand, the heavy metal fluoride BaY 2 f 8 Single crystal is a potential optoelectronic material. At present, BaY reported in domestic and foreign literature 2 f 8 Single crystals ...

Claims

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Application Information

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IPC IPC(8): C30B29/12C30B11/00
Inventor 阮永丰张守超李广慧孙伟李文润
Owner TIANJIN UNIV
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