Quantum electron transport through ultrathin Si films: effects of interface passivation on Fermi-level pinning.

We report first-principles calculations on electron transport through ultrathin silicon films between aluminum electrodes. The passivation of interface Si atoms at one side of the film with hydrogen makes the current-voltage characteristics asymmetric with quasirectifying properties. The low conductivity in this case can be explained by the weakened metal-induced gap states due to the passivation. We also demonstrate that the applied bias changes the strength of Fermi-level pinning for the passivated interface.