Abrupt metal-semiconductor interfaces

Unreactive metal-semiconductor systems are scarce but may serve as prototypes to understand the initial stages of the formation of Schottky barriers; they may provide a good medium in which to study coverage dependent structural arrangements, bonding characteristics, growth modes and development of the electronic properties. Lead group IV semiconductors are such model systems which have been thoroughly investigated by several groups in the last two years. In this paper we review the main findings adding new experimental results mostly derived from synchrotron radiation experiments in a broad temperature range.