Tight binding modeling of heterojunction band offsets as a function of pressure and composition

We present a new tight binding view of the heterojunction band offsets. The model considers the nonorthogonality of the sp(3) set of orbitals of adjac ent atoms and spin-orbit coupling and uses the Hartre-Fock atomic energies and interacting matrix clement, obtained by fitting bulk band structures of semiconductors, to determine the valence band energies at 0 K and 1 bar. T he valence band offsets are then obtained by aligning the temperature, pres sure, and composition dependent vacuum levels, screened by the optical diel ectric constants of bulk materials for thermodynamic equilibrium across het erointerfaces. Excellent agreement between the model predictions and experi ment fur the valence band offsets suggests that the bulk band structure pro perties play a significant rule in determining the band offsets for lattice matched heterojunctions and Schottky barriers.