A quantum thermomechanical modeling of band offsets and Schottky barriers of semiconductor heterostructures

Abstract

Using the extended universal tight binding model of semiconductors a new way of determining the band offsets and Schottky barrier heights in semiconductor heterostructures is presented. The band offsets and Schottky barriers are first determined by aligning the vacuum level, defined relative to valence band maximum and screened by optical dielectric constant of semiconductors, on both sides of heterojunction at zero temperature and standard pressure. The temperature, strain and pressure effects on band offsets and Schottky barriers are then obtained using the two statistical thermodynamic postulates: (i) the free electrons and holes are electrically charged weakly interacting quasichemical particles and (ii) the electron-hole pairs are generated by the charge transfer from bonding (valencelike) states to antibonding (conduction-like) states. Excellent agreement is obtained Between the model predictions and experiment for band offsets at interfaces between AlAs and GaAs and between HgTe and CdTe, as well as other heterojunctions and Schottky barriers.