Control of interface stoichiometry in InAs/GaSb superlattices grown by molecular beam epitaxy

Abstract
The InAs/GaSb materials system, with different species for both cations and anions, allows one to envision the construction of heterojunctions with either InSb- or GaAs-like interfaces. As a result, this system provides a unique opportunity to explore the limits of interfacial control that can be achieved at the monolayer level by vapor phase growth techniques. Using migration-enhanced epitaxial techniques, we have prepared a series of InAs/GaSb superlattices with both types of interfaces. The large differences in bond lengths and vibrational properties of InSb and GaAs interfaces allow x-ray diffraction and Raman spectroscopy to be sensitive probes of interfacial structure. The x-ray and Raman measurements reveal that it is possible to grow superlattices with almost pure InSb-like or GaAs-like interfaces.