Electrical properties of microcrystalline selenium

THE increasing number of electronic applications for semiconducting materials which have been developed in recent years, coupled with the discovery of the transistor action of these materials, has been largely responsible for the vast amount of research data which have been published on semiconductors. Most of the work has been done on germanium and silicon and as a result these data have led to a better understanding of the mechanism of electric conduction in semiconductors as well as an explanation of their rectification properties. Data such as these are lacking for selenium. The development of the selenium rectifier industry, however, during the past decade has stimulated an interest in its semiconducting properties. A limited amount of research work has been done on both single crystal and microcrystalline selenium, thinking that perhaps such data would aid in understanding the mechanism of conduction and also aid in overcoming some of the difficulties encountered in the manufacture of rectifiers. Several researchers have studied the electrical properties of single crystals of selenium with the thought that such data would serve to explain the electrical properties of microcrystalline selenium. These data have not materially clarified the situation. In view of these facts, and also since selenium exists in the microcrystalline state in selenium rectifiers, it would seem that measurements on the electrical properties of microcrystalline material would be the most practical contribution to existing data.