升华─提拉法生长碘化铋单晶

Single Crystal Growth of Bismuth Triiodide by Sublimation-pulling Method

碘化铋晶体具有大的三阶非线性效应，是研究非线性光学微观过程的最合适的材料。本文报道了碘化铋的合成、提纯以及升华－提拉生长大碘化铋单晶的工艺条件。获得尺寸为Φ１０×６０ｍｍ的大单晶，测得晶体的密度为５．８１ｇ／ｃｍ￣３，Ｘ射线衍射分析表明，室温下空间群为Ｒ－３，点阵常数为ａ＝０．７５２２ｎｍ，ｃ＝２．０７３ｎｍ。热分析显示从室温到４００℃之间的无相变。

Bismuth triiodide crystal has large value of the third-order nonlinear susceptibility.The material is suitable for the study of the microprocesses of nonlinear optical phenomena. In this paper the synthesis , purification and crystal growth of bismuth triiodied by sublimation-pulling methed are reported. The large size single crystal of Φ10×60mm was obtained,Its density is 5.81g/cm￣3 at 25 ℃. From X-ray diffraction analysis, the space group is R 3 and lattice parameters are a=0.725 5 nm and c=2.07 3nm.Thermal analysis shows no phase transition from room temperature to 400℃.