Space-charge limited conduction in insulators

Some of the fundamental problems associated with the electrical behavior of insulators involve contacts, space-charge effects, and high field phenomenon. CdS has a band-gap of 2.4 ev and ultra-pure crystals having relatively low imperfection densities are available. This paper is a review of some of the important features of conduction in insulators that are observed in CdS. The idea we wish to emphasize most here, is that of conduction by carrier injection. Insulators can pass relatively high current by this mechanism, and as methods are developed for producing better crystals, analytical techniques and devices based on this mode of conduction will become more important.