Conduction-band offset in a pseudomorphic GaAs/In0.2Ga0.8As quantum well determined by capacitance–voltage profiling and deep-level transient spectroscopy techniques

Abstract

The conduction-band offset ΔEC has been determined for a molecular beam epitaxy grown GaAs/In0.2Ga0.8As single quantum-well structure, by measuring the capacitance–voltage (C–V) profiling, taking into account a correction for the interface charge density, and the capacitance transient resulting from thermal emission of carriers from the quantum well, respectively. We found that ΔEC=0.227 eV, corresponding to about 89% ΔEg, from the C–V profiling; and ΔEC=0.229 eV, corresponding to about 89.9% ΔEg, from the deep-level transient spectroscopy (DLTS) technique. The results suggest that the conduction-band discontinuity ΔEC obtained from the C–V profiling is in good agreement with that obtained from the DLTS technique.