Interfacial atomic structure and band offsets at semiconductor heterojunctions

Abstract

The relationship between interfacial atomic structure and band offsets at semiconductor heterojunctions is explored through first-principles local density functional calculations. In particular, the effects of variations in interfacial geometry are analyzed for (001) interfaces between III–V/III–V materials. For the AC/BC case of a common atom, isovalent A–B intermixing in the noncommon atomic planes near the interface does not affect the band offset, even in the case of large lattice-mismatched systems. For quaternary AB/CD systems, there are two possible chemically abrupt interfaces (A–D or B–C); these can have offsets that differ by up to 80 meV. In those cases where the chemically abrupt AB/CD offset depends on the interfacial identity, intermixing leads to offset variations which are directly related to the offset difference between the chemically abrupt A–D and B–C interfaces. The differing behavior of common-atom versus noncommon-atom systems is analyzed in terms of the symmetry of the nearest-neighbor environment surrounding an atomic site of a composition change.