KDP晶体(100)面生长台阶聚并现象的AFM研究

AFM Investigation on Step Bunching on (100) Face of KDP Crystal

采用激光偏振干涉手段实时测量了KDP晶体(100)面的生长速度与过饱和度之间的关系,用AFM技术观察了KDP晶体(100)面在不同过饱和度下的基本台阶和聚并台阶形貌,并据此分析了由基本台阶到聚并台阶的过程及其与过饱和度之间的关系.研究表明:过饱和度为1.8%时,(100)面上以基本台阶为主,基本台阶的高度为0.366 nm,约为半晶胞高度;增大过饱和度,基本台阶开始聚并,聚并初期,台阶高度增加,进而台阶宽度增加;随着过饱和度的增大,台阶聚并加剧,推移速度加快,但聚并台阶的斜率基本不变.

The dependence of growth rate of （100） face of KDP crystal on supersaturation was measured using the laser polarization interference technique. Morphologies of both elementary steps and macrosteps were investigated by using AFM technique at a serial of supersaturation. Furthermore, the bunching process as well as the influence of supersaturation on bunching process was analyzed according to the AFM results. The results show that at the supersaturation of 1.8%, elementary steps are in priority on （100） face, whose height is 0.366 nm, equivalent to half of the unit cell. When the supersaturation is increased, elementary steps begin bunching together. At the initial bunching stage, the step height and step width are increased. With a rise of supersaturation, more elementary steps participate in the bunching process, and the velocity of the macrosteps increasease as well. At the same time, the slops of the macrosteps reach stable ultimately.