Observation of above-barrier quasi-bound states in asymmetric single quantum wells by piezomodulated reflectivity

Abstract

The piezomodulated reflectivity spectrum of asymmetric GaAs/AlGaAs single quantum well heterostructures display interband excitonic transitions from bound and quasi-bound valence states to bound and quasi-bound states in the conduction band. The quasi-bound states with maximum occupancy in the well region in these compositionally asymmetric quantum wells participate ‘‘resonantly’’ in interband transitions. These spectra are compared with those from symmetric quantum wells with the same well width.