Growth interfaces of crystals

晶体生长是材料科学与技术中最重要的技术之一，在晶体生长过程中弄清楚界面结构是一项有价值的研究，因为晶体的质量取决于生长单元在界面上的结合。对饱和溶液进行了精确的物理和化学研究，从现象学上分析了晶体生长。在生长界面处测量了晶体生长周围的浓度梯度和温度梯度，发现晶体的生长速率与梯度的法向分量成正比。由生长速率与浓度梯度之比得到的扩散系数与常规方法求得的溶质在溶液中的扩散常数吻合较好。由此提出，饱和溶液中溶质的分子状态与其结晶状态非常相似。界面上的粗糙度是晶体生长所必需的，然后用二维傅里叶变换讨论了界面结构的形态步骤，得到了界面上结构的空间频率。

Crystal growth is one of most impotant techniques in material science and technology and then it is a worth-while research to make clear structure of interfaces during crystal growth, because the quality of crystals will be determined by incorporation of the growth units at the interfaces.Physical and chemical studies on saturated solutions were done precisely to analyze the crystal growth phenomenologically. The concentration and temperature gradient around crystals growing in a two dimensional cell were measured at the growth interface, and the growth rate of the crystals was found to be proportional to the normal component of those gradient. The diffusion coefficient from the ratio of the growth rate to the concentration gradient is in a good agreement with the diffusion constant of the solute in the solution obtained by usual method. It is thus proposed that the molecular state of the solute in saturated solution is very similar to its crystalline state.A sort of roughness on the interface is necessary for crystal growth and then the morphological steps are discussed by using two dimensional Fourier transform to obtain spacial frequency of the structure on the interface.