Velocity-field characteristics of MgxZn1−xO/ZnO heterostructures.

In this work, electron transport in Mg_xZn_1−xO/ZnO heterostructures at room temperature is simulated by the ensemble Monte Carlo (EMC) method. Electron scattering mechanisms including acoustic deformation potential, piezoelectric acoustic phonon, polar optical phonon (POP), interface roughness (IFR), dislocation, electron escape (ESC) and capture (CPR) by optical phonons, and random alloy are considered in EMC. The electron drift velocity in Mg_xZn_1−xO/ZnO heterostructures is calculated for various Mg mole fractions x (0.1–0.3) at electric fields up to 25 kV/cm. We find that no obvious velocity saturation occurs in the range of the electric field considered. The results show that ESC scattering is one of the main physical mechanisms limiting the drift velocity. On the other hand, the competition between IFR and intersubband POP scattering is found to play an important role in the change in electron drift velocity with the increasing Mg mole fractions. [ABSTRACT FROM AUTHOR]