Some physical properties of thin films containing Se-Ge-Tl

Thin films from the Se45.5Ge30.3 Tl-24.2 system have been prepared by therm al evaporation. The current-voltage characteristics in the temperature rang e 290-373 K and the thickness range 98-400 nm are ohmic in the lower field regime followed by non-ohmic behaviour in the higher voltage regime which h as been satisfactorily explained by the anomalous Poole-Frenkel effect. The effects of temperature on the dielectric constant have been studied. The d ependence of the electrical conductivity, on exposure to different duration s of light and on temperature has been studied. The activation energy was f ound to decrease with increasing periods of light exposure. (C) 2000 Elsevi er Science Ltd. All rights reserved.