Mobility of large clusters on a semiconductor surface： Kinetic Monte Carlo simulation results

• Published in: Chinese physics B Vol. 25; no. 1; pp. 580 - 584
• Main Authors: Esen, M, Tüzemen, A T, Ozdemir, M
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.01.2016
• Subjects: Alpha rays; cluster mobility; Clusters; Computer simulation; Constants; Diffusion; Diffusion coefficient; diffusion constant; Monte Carlo method; Monte Carlo methods; Semiconductors; 动力学蒙特卡罗模拟; 动力学过程; 半导体表面; 团簇; 扩散系数; 正方形网格; 蒙特卡罗方法; 迁移率
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/25/1/013601

The mobility of clusters on a semiconductor surface for various values of cluster size is studied as a function of temperature by kinetic Monte Carlo method. The cluster resides on the surface of a square grid. Kinetic processes such as the diffusion of single particles on the surface, their attachment and detachment to/from clusters, diffusion of particles along cluster edges are considered. The clusters considered in this study consist of 150-6000 atoms per cluster on average. A statistical probability of motion to each direction is assigned to each particle where a particle with four nearest neighbors is assumed to be immobile. The mobility of a cluster is found from the root mean square displacement of the center of mass of the cluster as a function of time. It is found that the diffusion coefficient of clusters goes as D = A（T）Na where N is the average number of particles in the cluster, A（T） is a temperature-dependent constant and a is a parameter with a value of about -0.64 〈 a 〈 -0.75. The value of a is found to be independent of cluster sizes and temperature values （170-220 K） considered in this study. As the diffusion along the perimeter of the cluster becomes prohibitive, the exponent approaches a value of -0.5. The diffusion coefficient is found to change by one order of magnitude as a function of cluster size.