Modification of Heterojunction Band Offsets at III-V/IV/III-V Interfaces

III-V/IV semiconductor heterojunctions (with IV = Si, Ge, and III-V = GaAs, AlAs) as well as III-V/IV/III-V single and multiple quantum well structures have been synthesized by molecular beam epitaxy and characterized by a variety of in situ and ex situ characterization techniques. The goal wa's to investigate the composition profile achievable at the interface, the band discontinuities, the charged versus neutral character of the interfaces, and the dependence of the band discontinuities on the local interface environment. Relatively abrupt composition profiles can be achieved through appropriate growth protocols. Large deviations from the commutativity and transitivity rules of heterojunction band offsets in these systems are related to the establishment of inequivalent local interface environments. Such deviations can in principle be exploited to tune the band alignment in heterostructures.