扩散理论对RLA模型中交换作用的研究

A study based on diffusion theory for exchange-reaction of RLA model

以扩散理论为基础,建立以"基本微观过程"为核心的新模型,引入交换比的概念,对存在表面活化剂时薄膜生长的微观过程进行Kinetic Monte Carlo模拟.模拟发现,活化层原子和沉积原子都会发生跨层间的扩散,跨层扩散主要是单个原子的扩散,层间扩散的原子数目随着温度的升高或沉积厚度的增加而增多.RLA模型中的"交换作用"只是若干个"基本微观过程"的组合,大多数交换不是位置的"完全交换",交换比也并非恒为1.

In the research work, on the basis of the classic diffusion theory we have advanced a novel model of the reaction limited aggregation （RLA）, which involues the basic micro-processes. We firstly introduced the concept of exchange rate and have also simulated the growing process of surfactant-mediated epitaxial thin film growth with the kinetic Monte Carlo （KMC） method. By simulating, it was found that both surfactant atoms and adatoms would diffuse from one layer to another. This kind of diffusion mainly happens beween single atoms and the number of this diffusion increases with increasing growth temperature or increasing deposition depth. The exchange reaction of RLA model is the combination of several basic micro-processes. The majority of exchanges are not complete position exchange and the exchange ratio is not always equal to unity.