Quality of AlAs-like and InSb-like interfaces in InAs/AlSb superlattices: An optical study

Two short-period InAs/AlSb superlattices, grown with an AlAs-like interface and an InSb-like interface, respectively, were studied with Raman spectroscopy, x-ray diffraction, and ellipsometry. Our measurements show that the InSb-like interface grows perfectly pseudomorphically, whereas the sample with the AlAs-like interface shows indications of relaxation and As interdiffusion. This different interface quality seems to be a fundamental problem, rather than the result of the growth technique.