Conduction-band offset in a pseudomorphic GaAs/In_0.2Ga_0.8As quantum well determined by capacitance–voltage profiling and deep-level transient spectroscopy techniques

The conduction-band offset ΔE_C has been determined for a molecular beam epitaxy grown GaAs/In_0.2Ga_0.8As 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 ΔE_C=0.227 eV, corresponding to about 89% ΔE_g, from the C–V profiling; and ΔE_C=0.229 eV, corresponding to about 89.9% ΔE_g, from the deep-level transient spectroscopy (DLTS) technique. The results suggest that the conduction-band discontinuity ΔE_C obtained from the C–V profiling is in good agreement with that obtained from the DLTS technique. © 1998 American Institute of Physics.