Physics of Interfaces

Abstract

It has long been known that when a metal is placed in contact with a semiconductor a rectifying contact often results. This rectification is a result of an energy barrier between the metal and the semiconductor. In order to form a nonrectifying or ohmic contact, two general approaches can be applied: either (1) the barrier energy can be reduced to a low enough value that the thermally excited current over the barrier is large enough for the application involved or (2) the semiconductor can be doped to a high carrier density to allow quantum mechanical tunneling to take place. The physical principles of these processes are discussed in this article.