David J. Smith and Martha R. McCartney

Department of Physics, Arizona State University, Tempe, Arizona 85287-1504, USA

This talk will review some of our recent studies of heterovalent semiconductor interfaces and oxide/oxide or oxide/semiconductor heterostructures. The systems studied include several pairs of Group II-VI/Group III-V compound semiconductors with zincblende structure, and various oxides grown either on strontium titanate (STO) or on Si(001) and Ge(001) substrates. In the former pairs of semiconductor materials, lattice mismatch plays a major role in controlling the types of interfacial defects observed. For the oxides grown on STO, changes in the titanium oxidation state close to the interface result in the creation of a two-dimensional electron gas. For the oxide/semiconductor combinations, minimization of mismatch strain can be used as a strategy to control crystallographic orientation and hence the polarization direction.

Acknowledgments: Ongoing collaborations with the groups of Alex Demkov and John Ekerdt (University of Texas-Austin) and Yong-Hang Zhang (Arizona State University) are gratefully acknowledged.