高温氧化物晶体生长速度的本征波动性机理研究

项目名称： 高温氧化物晶体生长速度的本征波动性机理研究

项目编号： No.50802105

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 潘秀红

作者单位： 中国科学院上海硅酸盐研究所

项目金额： 20万元

中文摘要： 晶体生长过程中固液界面移动速度的波动，是产生晶体缺陷的主要原因之一，它影响到最终晶体的结构和性能。在稳定的生长条件下如何限制界面移动速度的本征性波动，对于获得高质量单晶材料是至关重要的。本项目利用高温晶体生长光学实时观察系统，以BaB2O4，KNbO3 等具有优异光学性能的氧化物单晶材料的高温熔液生长为研究对象，探索高温条件下晶体生长的本征波动性规律，对高温熔液中高度在微米尺度的亚宏观晶体台阶运动行为进行动态实时观察，分析生长动力学和热力学因素对高温台阶运动的影响以及台阶动力学理论在高温熔液生长中的适用性，结合晶体表面纳米级高度台阶聚并形貌的原子力显微镜分析，寻求晶体生长本征波动性的物理机制。该项研究将突破由于缺乏高温条件下台阶运动规律的了解而引起晶体尺寸、质量等方面的局限，在物理上为改进高温熔液晶体生长技术和制备完整的晶体材料提供可能的新思路以及可靠的实验依据。

中文关键词： 高温晶体生长；固液界面；本征波动性；亚宏观台阶

英文摘要： Fluctuations of growth rate with time typically result in structural defects in crystals, which deteriorate the crystal qualities. The fluctuation of growth rate, namely the moving velocity of solid-liquid interface, occurs even with constant conditions, which is an intrinsic character of crystal growth. Therefore the comprehension of intrinsic fluctuation mechanism is extremely important for design and achievement of high-quality crystals, especially for those crystals grown from high temperature melt which however has seldom been concerned in previous work. In this project the behavior of growth rate fluctuation and instability of interfacial morphology for oxide crystal at high temperature will be systematically studied based on the in situ optical observation of the solid-liquid interface movement as well as the propagation of macro-steps whose length scale is in order of several micrometers. The influence of interfacial kinetics and thermodynamics on the step advancing is also the main object of this work. In addition, the bunching of steps with height of several nanometers will be investigated by atomic force microscopy aiming at the deep understanding of physical mechanism for crystal growth fluctuations. The ultimate purpose of this project is to obtain more information of crystal growth rate fluctuation mechanism, as well as supply an effective method and some reliable data for the growth of perfect single crystals at high temperature. In the work, BaB2O4 and KNbO3 will be chosen for experimental studies on account of their excellent optical properties and the wide useful for commercial demand.

英文关键词： Crystal growth at high temperature; Solidliquid interface; Intrinsic fluctuation; Macrostep