PHOTOCONDUCTIVITY AND HIGH-FIELD CONDUCTION STUDIES IN AMORPHOUS THIN-FILMS OF SE-80-XTE20SBX

The present paper reports the temperature dependence of dark- and phot o-conductivities in vacuum-evaporated thin films of a-Se80 - xTe20Sbx with a view to see the effect of Sb addition to the binary Se80Te20 sy stem. The results indicate that the photoconductivity (sigma(ph)) incr eases along with the dark conductivity (sigma(d)) after the addition o f Sb to the binary Se80Te20 system. The relative photosensitivity, how ever, decreases upon Sb addition. The results are explained in terms o f the charged defect states. Current-voltage characteristics have also been studied and the results indicate that the dark current becomes s uper Ohmic at higher fields similar to 10(4) V/cm. An analysis of the experimental data indicates that a Poole-Frenkel-type conduction may b e responsible for the observed behaviour.