Double injection in solids with non-ohmic contacts. I. Solids without defects

Abstract

Electrical contacts to semiconductors or insulators are generally non-ohmic in most cases, and even though they can be made ohmic in some cases, they may become non-ohmic under certain bias conditions. The effects of electrical contacts on carrier transport in solids for one-carrier injection are well understood. This paper extends the consideration of such contact effects of two-carrier injection. On the basis of a simple physical model, an approximate theory of double injection in solids with non-ohmic contacts has been derived for solids without defects. It is shown that many unexpected aspects in electric conduction are associated with the interaction between charge carriers and contacts, and that there is no negative differential resistance regime in perfect or nearly perfect crystals with ohmic or non-ohmic contacts.