Optical and structural investigations of intermixing reactions at the interfaces of InAs/AlSb and InAs/GaSb quantum wells grown by molecular-beam epitaxy

Several issues related to the interface structure in molecular-beam epitaxially grown InAs/AlSb and InAs/GaSb heterostructures are investigated by Raman scattering, photoluminescence and X-ray measurements. The measurements reveal differing degrees of layer intermixing at the interfaces (IFs), greatest for AlAs-like IFs in the InAs/AlSb material system, less pronounced for GaAs-like IFs in the InAs/GaSb material system, and smallest for InSb like IFs in both systems. This intermixing is both thermodynamically favoured and, in addition, driven by a lowering of the strain-induced component of the surface energy.