Comparison of vacancy and antisite defects in GaAs and InGaAs through hybrid functionals

The formation energies and charge transition levels of vacancy and antisite defects in GaAs and In0.5Ga0.5As are calculated through hybrid density functionals. In As-rich conditions, the As antisite is the most stable defect in both GaAs and InGaAs, except for n-type GaAs for which the Ga vacancy is favored. The Ga antisite shows the lowest formation energy in Ga-rich conditions. The As antisite provides a consistent interpretation of the defect densities measured at mid-gap for both GaAs/oxide and InGaAs/oxide interfaces.