ZTS晶体(100)面生长过程的实时AFM研究

In-situ AFM Study on Growth Process of the (100) Face of ZTS Crystal

利用原子力显微镜(AFM)对不同生长条件下ZTS晶体(100)面生长过程进行实时观测发现,(100)面均呈现为台阶面,台阶分单台阶、聚并台阶和准聚并台阶3种。位错、缺陷和二维成核均可形成单台阶;聚并台阶以整体推移的方式生长,而准聚并台阶内的单台阶保持单台阶推移的特点。单台阶的推移展现出明显的各向异性。聚并台阶的聚并程度随着过饱和度增大而增大;台阶簇内台阶合并和不同生长源生成的沿不同推移方向推移的台阶相互影响引起台阶运动失稳均能导致聚并台阶的形成;聚并台阶列同步向前推移体现出生长的稳定性,随着生长进行,生长台阶各个位置的过饱和度差异会导致稳定性遭到破坏。另外发现,晶体表面存在优先成核位置,优先成核位置位于台阶边缘,且成核过程遵循成核—扩展—再次成核的规律性。

In-situ atomic force microscopy （AFM） method has been applied to real-time observation over the growth process on the （100） face of ZTS crystals under different conditions. It comes out that the （100） face is manifested to be step-faeeting, inclu- ding the elementary steps, macrosteps and quasi-macrosteps. The elementary steps originate from dislocations, defects and two-di- mensional nuclei. The macrosteps advance as a whole, but the steps which assembled in the quasi-macrosteps keep the motion charac- teristics of elementary steps. The advancement of elementary steps shows significant characteristics of anisotropy. The bunching le- vel of step increases obviously with a rise of supersaturation. Besides the mergence of steps among the step cluster, the formation of macrosteps also result from the instability of step motion which is caused by the interaction of steps generating from different sources and moving in different directions. The stability of growth is reflected by the synchronous advance forward of the bunching step se- ries. However, the stability can be destroyed owing to the different supersaturation at diverse locations of the growth steps. In addi- tion, results indicated that the sites of preferential nucleation appear on the crystal surface, and preferential nucleation occurs at the step edges and has the regularity of nucleation-spreading-re-nucleation.