Conduction-band offset in pseudomorphic GaAs/In_0.2Ga_0.8As quantum well determined by C-V profiling and DLTS techniques

The conduction-band offset ΔE_c has been determined for molecular beam epitaxy (MBE) grown GaAs/In_0.2Ga_0.8As single quantum well structure, by measuring the capacitance-voltage profiling, while taking into account a correction for the interface charge density, and the capacitance transient resulting from thermal emission of carrier 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