INTERFACE COMPOSITION CONTROL IN INAS/GASB SUPERLATTICES

The GaSb/InAs materials system, with two species of both cations and anions, permits the construction of heterostructures with either InSb- or GaAs-like interfaces. As a result, this system provides an opportunity to explore the limits of interfacial control that can be achieved by vapor phase growth techniques. We have characterized a series of superlattices (SLs) prepared with both types of interfaces by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and photoconductivity. The large differences in bond lengths, electronic properties and vibrational properties of InSb and GaAs interfaces allow these techniques to be sensitive probes of interfacial structure. By carefully measuring and minimizing the group V cross-contamination in the SL layers, we are able to unambiguously demonstrate the growth of SLs with almost pure InSb-like or GaAs-like interfaces.