Chemical bonding and Fermi level pinning at metal-semiconductor interfaces

Since the time of Bardeen, Fermi level pinning at metal-semiconductor interfaces has traditionally been attributed to interface gap states. The present work shows that polarized chemical bonds at metal-semiconductor interfaces can lead to the apparent Fermi level pinning effect. Good agreement with various systematics of polycrystalline Schottky barrier height experiments has been found. These findings suggest that chemical bonding is a primary mechanism of the Schottky barrier height.