The Effects of Pressure and Temperature on the DC and AC Conductivities of Heavily Doped Amorphous Semiconductors.

A number of theories, which were proposed to explain ac conductivities in disordered materials, are compared. The predicted temperature and pressure dependences of both the ac and dc conductivities and ac dielectric constants are discussed. The methods of sample preparation are presented with special consideration given to problems of preparing samples for electrical transport measurements. The designs of high pressure systems which were used are described, and the advantages, capabilities, and the operational techniques and problems are compared for the different systems. The dc conductivities of a number of Te-As-Ge glasses as functions of pressure and temperature were measured. Numerous attempts were made to observe frequency-dependent conductivity in these glasses and in a number of other bulk glasses for which it was reported in thin film samples.