A theoretical study of the initial oxidation of the GaAs(001)-β2(2x4) surface

The early stages of the oxidation of the GaAs(001)-beta 2(2x4) surface are investigated theoretically by ab initio molecular dynamics simulations. An atomistic mechanism of formation of structural defects at the interface is described. The electronic properties of the GaAs/oxide interface are computed and it is found that energy levels within the bandgap are associated with the generated interfacial structural defects. These results provide an atomistic description of the nature of the defects at the origin of the Fermi level pinning in III-V's as well as the mechanism underlying their generation. (C) 2009 American Institute of Physics. [doi:10.1063/1.3275737]