Effects of copper content and heat treatment on the electrical properties of Ge15Te85-xCux thin films

The mechanism of incorporation of copper in amorphous films of Ge15Te85-x C u-x (0 less than or equal to x less than or equal to 7 at.%) system and the effect of heat treatment are studied by measuring the de conductivity in t he temperature range (150-423 K). The results indicates that there are two conduction mechanisms. For temperature above 330 K, conductivity exhibits a ctivated behaviour, while in low temperature range (T = 150-300 K) conducti vity exhibits non-activated behaviour. In the high temperature region, resi stance and the activation energy have been calculated. The decrease in the activation energy on addition of Cu has been interpreted according to the K astner model. In the low temperature region Mott's parameters have been eva luated and they are decreased with Cu content; the results in this region a re interpreted following Mott's model. (C) 2000 Published by Elsevier Scien ce B.V.