Photocurrent and Photoluminescence Investigations of GaInNAs and GaInNAs(Sb) Quantum Wells Grown by Molecular Beam Epitaxy

Abstract

We have investigated photocurrent (PC) and photoluminescence (PL) in sequentially grown GaInNAs/GaAs and GaInNAs(Sb)/GaAsSbN quantum wells. Photocurrent transitions are analyzed by theoretical calculations using envelope function formalism taking into account the strain effect and the strong coupling between nitrogen localized state and the GaInAs band gap. The results are consistent with a type I band alignment and a conduction band offset ratio of about 80 %. Additionally, our results suggest an increase of the electron effective mass by as much as 0.035 m₀ resulting from the flattening of the conduction band under nitrogen effect. The temperature evolution of the PL peak energy and the integrated PL intensity of GaInNAsSb QW show evidence of strong localization of carriers. Both, the high delocalization temperature, in the 230 K range and the strong shift between the PC and PL spectra of GaInNAsSb QW, indicate the presence of deeper localized states as compared to that in the GaInNAs QW.