Optical characterization and determination of conduction band offset of type-II GaAsSb/InGaAs QW
The optical property of a GaAsSb/InGaAs type-II quantum well (QW) was studied and the conduction band discontinuity (ΔEc) was determined by spatially indirect radiative transitions. ΔEc between GaAs0.73Sb0.27 and In0.19Ga0.81As was measured to be −210 meV, which showed that the heterojunction was highly staggered. For the type-II QW, radiative transition efficiency was decreased with the increase of interband transition wavelength. It was explained by the reduction of overlap between electron and hole functions. By optimizing transition wavelength and efficiency of the type-II QW, strong photoluminescence was observed around 1.3 µm at room temperature.