Boron-induced electronic states in hydrogenated amorphous silicon

Abstract

The electronic densities of states of the bonding structures containing threefold and fourfold coordinated boron are studied. The bonding configurations with and without a B H bond are considered. The threefold coordinated B configuration has a deep defect state in the gap. It is derived from the non-bonding p z . state. There is no deep defect state induced by the fourfold coordinated B configuration. There is an empty band near the top of the valence band for the fourfold coordinated B that acts as hole-like carrier. A further study indicates that the bonding configurations with a B H bond can give lower formation energy than those without a B H bond.