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


Esen M., Tuzemen A. T., Ozdemir M.

CHINESE PHYSICS B, cilt.25, sa.1, 2016 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 25 Sayı: 1
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1088/1674-1056/25/1/013601
  • Dergi Adı: CHINESE PHYSICS B
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sivas Cumhuriyet Üniversitesi Adresli: Evet

Özet

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) N-alpha 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 < alpha < -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.