INTERFACIAL ATOMIC-STRUCTURE AND BAND OFFSETS AT SEMICONDUCTOR HETEROJUNCTIONS

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.