中国物理B ›› 2016, Vol. 25 ›› Issue (1): 13601-013601.doi: 10.1088/1674-1056/25/1/013601

• ATOMIC AND MOLECULAR PHYSICS • 上一篇    下一篇

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

M Esen, A T Tüzemen, M Ozdemir   

  1. 1. Vocational School of Adana, Cukurova University, Adana 01160, Turkey;
    2. Department of Science and Mathematics Education, Faculty of Education, Cumhuriyet University, Sivas 58140, Turkey;
    3. Department of Physics, Cukurova University, Adana 01330, Turkey
  • 收稿日期:2015-06-15 修回日期:2015-08-04 出版日期:2016-01-05 发布日期:2016-01-05
  • 通讯作者: M Esen E-mail:mesen@cu.edu.tr

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

M Esen1, A T Tüzemen2, M Ozdemir3   

  1. 1. Vocational School of Adana, Cukurova University, Adana 01160, Turkey;
    2. Department of Science and Mathematics Education, Faculty of Education, Cumhuriyet University, Sivas 58140, Turkey;
    3. Department of Physics, Cukurova University, Adana 01330, Turkey
  • Received:2015-06-15 Revised:2015-08-04 Online:2016-01-05 Published:2016-01-05
  • Contact: M Esen E-mail:mesen@cu.edu.tr

摘要: 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)Nα where N is the average number of particles in the cluster, A(T) is a temperature-dependent constant and α is a parameter with a value of about -0.64< α <-0.75. The value of α 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.

关键词: diffusion constant, cluster mobility, Monte Carlo method

Abstract: 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)Nα where N is the average number of particles in the cluster, A(T) is a temperature-dependent constant and α is a parameter with a value of about -0.64< α <-0.75. The value of α 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.

Key words: diffusion constant, cluster mobility, Monte Carlo method

中图分类号:  (Diffusion and dynamics of clusters)

  • 36.40.Sx
68.43.Jk (Diffusion of adsorbates, kinetics of coarsening and aggregation) 68.43.Mn (Adsorption kinetics ?) 05.10.Ln (Monte Carlo methods)