Transient photoconductivity in amorphous Se70Sb20Ag10 thin films

Se70Sb20Ag10 bulk material was obtained using a conventional melt quenching technique. Thin films of a-Se70Sb20Ag10 were prepared by vacuum evaporation technique in a base pressure of 10−4 mbar onto well-cleaned glass substrates. Dark, light conductivity and transient photoconductivity have been studied. The photoconductivity increases initially and then saturates with time when illuminated with low intensity light (<400 Lux); however, when illuminated with higher intensity light (>600 Lux) the photoconductivity increases initially, attains a maximum and then decreases with time. This behavior of photoconductivity has been studied at various temperatures. The results have been explained on the basis of Dember voltage and the interaction between photoexcited holes and the trapped electrons on the surface.