Observation of quasibound states in semiconductor single quantum barriers

We report the observation of quasibound states in single semiconductor barriers, in heterostructures with both type-I and type-II band alignments. We disucss the localization and the shape of wave functions of such states, as well as their density of states. In structures with type-II band alignment (CdSeZnTe and CdMnSe/ZnTe) we observe transitions involving electrons confined in the conduction band well and quasibound holes localized in the valence band barrier (both in the CdSe layer). In the system with type-I band alignment (ZnMnSe/ZnSe) transitions between states quasibound in the single ZnMnSe barrier also show clear absorption peaks.