铝酸钇晶体中的生长小面

采用提拉法生长了掺Ce、掺Yb和掺Mn的铝酸钇(YAlO3,YAP)晶体,晶体均完整透明,无肉眼可见的气泡、散射和包裹物等宏观缺陷。通过化学腐蚀和同步辐射白光形貌实验检测了YAP晶体中的生长小面缺陷。结果表明:晶体生长过程中,由于凸向熔体的固-液界面,造成了小面生长现象。沿[101]方向生长的YAP晶体中出现的小面为(102),(201),(121)和(121)奇异面。X射线摇摆曲线表征的结果表明:生长小面的存在严重破坏了晶体的微观结构完整性和均匀性,并导致了小角度晶界缺陷的产生。

Ce-, Yb- and Mn-doped yttrium aluminate (YAlO<inf>3</inf>, YAP) crystals were successfully grown by the Czochralski method. The growth facet and related microscopic defects in YAP crystals were investigated by chemical corrosion method and synchrotron radiation topography experiments. The results show that the obtained crystals were transparent and had no macroscopic defects such as bubbles, scatters or inclusions. The solid-liquid interface used for growing these crystals has a conical shape, convex into the melt. Thus this interface leads to the appearance of growth facet defects. The growth facet defects appearing in [101]-oriented grown YAP crystal were (102), (201), (121) and (12¯1) singular planes. The results of X-ray rocking curve measurement indicate that the crystallization perfection and homogeneity of the crystal are destroyed by the existence of growth facet defects, and they are the main factors causing low-angle grain boundary defects.