Segregation phenomena of As in GaAs at different cooling rates during solidification

Abstract

In this study, the solidification processes of liquid GaAs were investigated by molecular dynamics simulation at different cooling rates of 1010 K/s, 2 × 1010 K/s, 5 × 1010 K/s, 1011 K/s, 1012 K/s, and 1013 K/s. The structural evolution of GaAs was investigated in detail by the radial distribution function, average atomic energy, average coordination number, and visualization technology. The results show that segregation phenomena occur to different extents during the quenching of GaAs at the six cooling rates. The segregation areas of As tend to be simple cubic structures that are considerably influenced by the cooling rate. For a cooling rate of 5 × 1010 K/s, the system forms a large number of segregation structures at a crystallization temperature of approximately 690 K. When the temperature is higher than the crystallization temperature, the As atoms of the segregation areas are in a disordered state, whereas at a lower temperature, some of the As atoms in the segregation rapidly crystallize to form the simple cubic structure.