邻晶面外延生长机制的动力学Monte Carlo模拟

用动力学Monte Carlo模拟方法研究了GaAs(001)邻晶面的外延生长机制.Ehrlich-Schwoebel势垒对邻晶面外延机制有重要的影响.模拟结果显示，低温下Ehrlich-Schwoebel势垒几乎能完全阻止原子向下一台阶面的迁移，高温下原子已能有效地克服势垒的影响并向下一台阶面迁移.在外延生长初期，原子几乎在台阶面上均匀分布.当表面覆盖度达到一定数量后，台阶成核开始.而由于Ehrlich-Schwoebel势垒的存在，在台阶的上侧台阶面上开始有原子的积累，而如果没有Ehrlich-Schwoebel势垒，台阶上侧台阶面上的原子也能被有效地耗尽.Ehrlich-Schwoebel势垒对邻晶面上的外延生长模式有显著的影响，将明显提高达到台阶生长模式的温度. 关键词： 外延生长模式 动力学Monte Carlo Ehrlich-Schwoebel势垒

Kinetic Monte Carlo simulation of the epitaxial growth mechanism on the vicinal surface

In this paper the epitaxial growth mechanism on vicinal GaAs(001) surface is studied using the kinetic Monte Carlo simulation method. The Ehrlich-Schwoebel barrier has great influence on the growth mechanism of the vicinal surface. The simulation results show that the downward movement to a lower step of the adatoms can be inhibited by Ehrlich-Schwoebel barrier at low temperature, while the adatoms can move to the lower step at high temperature. At the beginning of growth, the adatoms are almost distributed uniformly on the steps. When the surface coverage reaches to certain value, the step nucleation begins. Meanwhile, the adatoms begin to accumulate at the upper step because of the Ehrlich-Schwoebel barrier. If there were no Ehrlich-Schwoebel barrier, the adatoms at the upper step could be depleted completely. The Ehrlich-Schwoebel barrier has great influence on the growth mode of the vicinal surface, and it will increase the temperature for onset of the step growth mode.