Monte Carlo and Molecular Dynamics Simulations of Liquid Semiconductor Surfaces

ABSTRACTWe have numerically studied the surface tension and surface profiles of several liquid semiconductors, including Si, Ge, GaAs, CdTe, and their alloys, as a function of temperature and concentration. Two kinds of simulations have been carried out: direct free-energy calculations using Monte Carlo methods, and force summations using molecular dynamics. We use empirical two- and three-body interatomic interactions based on the form originally proposed by Stillinger and Weber for Si, in conjunction with simulation cell sizes ranging from 216 to as large as 8000 atoms and several novel numerical techniques including a direct calculation of the surface entropy. In the case of alloys, we find a striking segregation of the low-surface-tension component to the surface even when the alloy components are miscible at all concentrations.