KDP晶体台阶生长动力学的激光干涉实验研究

A Study on the Step Growth Kinetics of KDP Crystal by Michelson Laser Interferometer Experiment

采用迈克尔逊干涉技术 ,通过测量KDP晶体生长的法向速率和台阶斜率来研究其台阶生长的动力学系数、台阶自由能、溶质在边界层内的扩散特征以及激发晶体生长台阶的位错活性 .实验表明 ,KDP中不同活性位错的台阶动力学系数差异较大 ,例如高活性和低活性台阶动力学系数分别为 10 .3× 10 -2 和 5 .2 1× 10 -2 cm/s,位错源在晶体表面的形状、面积的变化 。

s The dislocation hillock slope and the normal growth rate determined by this dislocation source were simultaneously measured by using the Michelson laser interferometer technology. The crystal growth kinetic parameters, including the step growth kinetic coefficient and step free energy are measured or calculated and the mass diffusion characters on the step plane and the activity of different dislocation sources are discussed. It has been shown that the step kinetic coefficients have significant differences between high and low-activity dislocation sources. For example, the step kinetic coefficients are calculated to be 10.3×10 -2 and 5.21×10 -2 cm/s for high-activity and low-activity steps, respectively. The most important conclusion is that the surface diffusion does not play a noticeable role in the crystal growth of KDP. It has been believed that the variations of the shape and size of dislocation sources, along with the change of Burgers vectors, are the main reasons for the poor repeatability of kinetic experimental data of KDP crystals.