Optical properties of atomic layer grown InAs/AlSb quantum well structures by gas source migration enhanced epitaxy

InAs/AlSb quantum well (QW) structures with InAs buffer layers are grown on (001) GaSb substrates by gas source MEE (migration enhanced epitaxy). PL (photoluminescence) measurements show that the optical properties of InAs/AlSb QWs strongly depend on the shutter sequence at the interfaces and therefore the type of the heterointerfaces (InSb-type, AlAs-type). 77 K PL intensity from the QWs with InSb-type interfaces is much stronger than that with AlAs-type interfaces. Furthermore, the temperature variation of the former is much weaker than that of the latter. However, the 4.2 K PL intensity is on nearly the same level for both types. PL peak energy is also dependent on the heterointerface types, which is explained by taking account of the potential profiles at the interfaces; the InSb-type interfaces increase the effective thickness of the InAs wells. These optical properties are different from those of the InAs/AlSb QWs with AlSb buffer layers. The origin of the difference is discussed.