Growing method for carbon-doped sapphire crystal

A growth method and crystal growth technology, applied in crystal growth, single crystal growth, single crystal growth, etc., can solve problems such as difficulty in ensuring uniform distribution of C, difficulty in obtaining uniform quality, low effective atomic number, etc., and achieve excellent thermoluminescence Performance, good crystal quality, high sensitivity results

Inactive Publication Date: 2008-07-30
SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (2) The luminescence peak type near 187°C is single, and the effective atomic number is relatively low (10.2)
The premise of this method is to grow a high-quality rod-shaped sapphire crystal, and then reduce and anneal. The process is relatively complicated, and it is difficult to ensure the uniform distribution of C in the sapphire crystal, that is, it is difficult to obtain α-Al with uniform quality 2 o 3 :C crystal

Method used

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  • Growing method for carbon-doped sapphire crystal
  • Growing method for carbon-doped sapphire crystal

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Example 1: α-Al with a C doping amount of 5000ppm 2 O 3 : C crystal growth

[0026] Weigh 500 grams of α-Al 2 O 3 Mix with 2.50 grams of graphite, which is 5000 ppm, in a mixer for 24 hours, and pack them in a fresh-keeping bag for later use. Put the R(0112) direction oriented seed crystal into the seed crystal groove at the tail of the molybdenum crucible of φ50×80mm, put the prepared powder into the crucible evenly, and cover the crucible lid. Put the side insulation screen so that the crucible is in the center of the cylinder, then cover the top insulation screen in turn, and finally cover the bell jar. Turn on the mechanical pump and vacuum to 5×10 -3 Pa, turn on the power supply and continue to heat up to 2353K, keep the temperature constant for 1 hour, then cool down to room temperature at a rate of 5°C / hour, open the furnace cover, and take out the crystals.

[0027] After inspection, the α-Al of this embodiment 2 O 3 : C crystals are intact, without obvious inclusio...

Embodiment 2

[0028] Example 2: α-Al with 100 ppm C doping 2 O 3 : C crystal growth

[0029] Except that the added graphite C is 100 ppm, and the temperature is lowered to room temperature at a rate of 3° C. / hour to grow crystals, other ingredients and growth steps are the same as in Example 1. Α-Al from growth 2 O 3 :C crystal, the crystal structure is complete, no obvious inclusions and bubbles appear. The intensity of the F color center of the crystal at 206nm and the thermoluminescence intensity at 187℃ are relatively reduced, but the position of the thermoluminescence peak at 187℃ does not change.

Embodiment 3

[0030] Example 3: α-Al with a C doping amount of 2500ppm 2 O 3 : C crystal growth

[0031] Except that the added graphite C is 2500 ppm, the temperature is lowered to room temperature at a rate of 4° C. / hour to grow crystals, and other ingredients and growth steps are the same as in Example 1. Α-Al from growth 2 O 3 : C crystal, complete crystal structure, no obvious inclusions and bubbles, with α-Al 2 O 3 :C crystal is located at the characteristic thermoluminescence peak of 187℃, and the F color center intensity at 206nm is larger.

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Abstract

The invention relates to a method of growing a carbon-mixed sapphire crystal, is characterized in that the method of targeted gradient temperature is adopted to grow the Alpha-Al2O3: C crystal. The process flow is as follows: firstly, a certain qualitative amount of Alpha-Al2O3 is weighed and then graphite of 100 to 5,000 ppm is added in and stirred to mix well; secondly, oriented sapphire seed crystals are placed in the seed crystal tank of the molybdenum crucible in the temperature gradient furnace and the well-mixed powder lot is put into the crucible evenly and then the crucible is covered; and thirdly, the crucible is placed in the furnace. The furnace is vacuumized to be 5 by 10<-3>Pa, persistently overheated to be 2,080 DEG Cand kept constant for 0.5 to 1 hour and then the temperature is reduced to the room temperature at a velocity of 3 to 5 DEG C per hour and then the furnace mantle is unclosed to take out the crystal. The Alpha-Al2O3: C crystal directly grown in the invention has excellent thermoluminescence capability and high crystal quality, which can be used for manufacturing highly-sensitive thermoluminescent detectors.

Description

Technical field [0001] The present invention relates to carbon-doped sapphire crystals (hereinafter referred to as α-Al 2 O 3 :C) Crystals, especially a method for growing carbon-doped sapphire crystals. Using the Directional Temperature Gradient Technique (DTGT) to grow larger size α-Al 2 O 3 :C crystal, α-Al 2 O 3 The main function of :C crystal is to make thermoluminescence detector. Background technique [0002] M.S.Akselrod first discovered α-Al in the 1990s 2 O 3 : C crystal has very excellent thermoluminescence performance, the luminescence peak temperature is 187℃, the peak half-height width is 60℃, the thermoluminescence sensitivity is 40-60 times that of LiF:Mg, Ti, and the background threshold dose is only 10 -6 Gy (Grey, hereinafter referred to as Gy), its dose response is linear and sub-linear, and the linear range is 10 -6 ~10Gy. α-Al 2 O 3 : After the C crystal is irradiated, the peak wavelength of the heated luminescence is 420nm, mainly due to the heated electron...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/20C30B11/00
Inventor 杨新波徐军李红军赵广军周国清苏良碧
Owner SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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