Systematic theoretical investigations for miscibility of ganxas1xybiy thin films

Abstract

The atomic arrangements of zinc blende structured GaNxAs1xyBiy thin films coherently grown on GaAs(001) substrates are theoretically investigated using empirical interatomic potentials and Monte Carlo simulations. The resultant atomic arrangements of GaNxAs1xyBiy strongly depend on N composition x and substrate lattice parameter asub. It is found that the incorporation of N atoms in GaAsBi results in the formation of layered structures consisting of GaN, GaAs, and GaBi regions. This is because Ga-N interatomic bonds tend to be located around Ga-As interatomic bonds to approach its equilibrium bond length. Furthermore, either GaBi or GaN surface segregation appears to reduce the strain caused by lattice constraint. These results suggest that the miscibility of GaNxAs1xyBiy thin films can be controlled by choosing suitable lattice constraint varied by x and asub that approach the bond length of the equilibrium values for semiconductor material. © 2014 The Surface Science Society of Japan.