Electrical conductivity and thermoelectric power in amorphous As2Se3Tlx semiconductors

Dc conductivity and thermopower measurements as a function of temperature have been performed on solid As₂Se₃Tl_x glasses with x ranging from 0 to 1.99. Investigations have been extended to low temperatures. By substitution of Tl the conductivity can be increased by more than 5 orders of magnitude without changing the type of transport mechanism. Band-like conduction is observed with holes being the dominant charge carriers. The three-dimensional network of As₂Se₃ is assumed to be modified by the Tl atoms; this leads mainly to a decrease in the activation energy.