Strain effects on the interface properties of nitride semiconductors

Abstract

An ab initio study of nitride-based heteroepitaxial interfaces that uses norm-conserving pseudopotentials and explicitly treats the strain due to lattice mismatch is presented. Strain effects on the band offsets range from 20% to 40%. The AlN/GaN/InN interfaces (with AlN in-plane lattice constant) are all of type I, while the ${\mathrm{Al}}_{0.5}$ ${\mathrm{Ga}}_{0.5}$N/AlN zinc-blende (001) interface is of type II. Further, the bulk polarizations in wurtzite AlN and GaN are -1.2 and -0.45 μC/${\mathrm{cm}}^2$, respectively, and the interface contribution to the polarization in the GaN/AlN wurtzite multiquantum-well is small.