Volume defects of crystal structure in alkali halide crystals grown from melt by continuous automated method

• Дата: 2008
• Автори: Goriletsky, V.I., Tymoshenko, M.M., Vasyliev, V.V., Ilyashenko, T.O.
• Формат: Стаття
• Мова: English
• Опубліковано: НТК «Інститут монокристалів» НАН України 2008
• Назва видання: Functional Materials
• Теми: Technology
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/136542
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Volume defects of crystal structure in alkali halide crystals grown from melt by continuous automated method // V.I. Goriletsky, M.M. Tymoshenko, V.V. Vasyliev, T.O. Ilyashenko // Functional Materials. — 2008. — Т. 15, № 4. — С. 550-555. — Бібліогр.: 4 назв. — англ.

The types of crystal structure defects (CSD) and the formation causes thereof in Csl(Na), Csl(TI), and Nal(TI) crystals of 290 to 520 mm diameter are considered. It has been shown that the CSD of impurity capture type are formed mainly due to disturbed crystallization equilibrium caused by a sharp change in the heat transfer from the growing crystal to water-cooled growth furnace walls. In the ROST units of two generations differing in size and thus in the growing crystal dimensions, this occurs at the height of the crystal cylindrical part of 50 and 70 mm, respectively. The CSD in the form of a local deterioration of the crystal transparence can arise at any crystal height after its exit from the crucible. Those are due to local changes in the crystallization front (CF) shape caused by the temperature variation rate of the controlling heater exceeding the permissible one. This process is accompanied by the crystal diameter increase and acceleration of the crystal linear growth at the CF.