Bi_(12)SiO_(20)晶体生长及其形态

Bismuth Silicate Crystal Grown by CZ Method and Its Shape Changes

采用浮称自动等径技术提拉生长出〈001〉、〈110〉及〈111〉三种取向的Bi_(12)SiO_(20)单晶(简称 BSO)。尺寸达Φ35×65mm。文中揭示了不同取向生长 BSO 单晶的形态显露规律,并从晶体结构和晶体生长形态学的角度分析讨论了生长过程中 BSO 晶体的形态演变,指出极性{112}晶面的存在是〈110〉、〈111〉晶体生长过程中形态演变的内在原因。选择适合的转速、保证晶体在良好的晶形下生长是生长质量高、利用率高的 BSO 大单晶的关键。

The bismuth silicate (BSO) crystals grown by CZ method arereported.The BSO crystals were pulled along <001>,<110>,and <111> direc-tionswith diameters controlled automatically by the buoyant force balanceset-up.The size of BSO is (?)35×65mm.The proper pull rates were about2.5mm/h,the rotation rates were about 25～35r/min,and the verticaltemperature gradient (under the surface of melt,10mm) was about 50℃/Cm.The crystals grown under these conditions have good shapes and high quality.The habits of BSO-crystal grown along different directions have been discussed.The changes of crystal shapes during crystal growth according to the crystalstructure and crystal growth morphology are also analysed.It is suggested thatthe polar of <112> directions give rise to the changes of crystal shapes andone of the keys to produce large BSO crystals with high optical quality and high utilization ratio is to keep the crystals in good shapes during the crystal growth.