Defect energy levels of the As–As dimer at InGaAs/oxide interfaces: A first principles study

Abstract

Display Omitted HighlightsWe model abrupt, defect-free InGaAs/Al2O3 interfaces.We describe the procedure to achieve an As-As dimer at the interface.In all steps of the model construction electron counting rule is strictly satisfied.Charge transition levels are determined within an accurate density-functional scheme.Results rule out the As-As dimer as possible origin of band-gap states. Charge transition levels of the As-As dimer defect at the InGaAs/Al2O3 interface are determined through density-functional calculations. At variance with the GaAs/Al2O3 interface where this defect gives rise to states within the band gap, its defect levels at the InGaAs/Al2O3 interface lie well above the conduction-band edge, irrespective of the composition of the first-neighbor shell surrounding the defect. These results rule out the As-As dimer as possible origin of band-gap states at InGaAs/Al2O3 interfaces.