Interface properties for GaAs/InGaAlP heterojunctions by the capacitance-voltage profiling technique

Abstract
The conduction-band discontinuity ΔEc and interface charge density σ have been studied for GaAs/In0.5(Ga1−xAlx)0.5P heterojunctions, prepared by metalorganic chemical vapor deposition. The dependences of ΔEc and σ on Al composition x were investigated for x from 0 to 1. The In0.5Al0.5P/ In0.5Ga0.5P heterojunction was also examined. The results suggest that the valence-band discontinuity ΔEv for GaAs/In0.5(Ga1−xAlx)0.5P is a linear function of x and is larger than ΔEc, being in reasonable agreement with results on the InAlP/InGaP heterojunction. The σ values for GaAs/InGaAlP were found to be one order of magnitude larger than those for GaAs/AlGaAs and InAlP/InGaP heterojunctions.