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lliang921(金币+15, 翻译EPI+1): 2011-02-28 10:17:18
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For the first time the optical floating zone method is used to grow XXX single crystals, with a rotation rate of 30 rpm under an air atmosphere. Results reveal that XXX single crystals have been grown at a growth speed of 6 mm/h. The as-grown sample has the size of Ф 4-6 mm × L 87 mm, with the largest crystal domain being Ф 5 mm× L 32 mm. The as-grown crystal was dark brown in color, which fades to light brownish after annealing in the oxygen atmosphere. The single crystal grown along c-axis direction and the cleavage plane can be indexed to b- axis direction. The crystal is free of low angle grain boundary and inclusion. The photoluminescence spectrum of the crystal has a strong blue emission band centered at 435 nm. The oxygen vacancies of the as-grown crystal can be eliminated by the annealing process in the oxygen atmosphere, which results in the change of color of the crystal, the narrowing of FWHM of the XX stretching band (905 cm-1) and the increase of the blue emission intensity. |
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