Effect of Ag additive on the photoconductive properties of (Se80Te20)100−xAgx (1 ≤ x ≤ 4) thin films
Semiconductors Laboratory, Department of Physics, Guru Nanak Dev University, Amritsar 143005, Punjab, India
Revised: 25 April 2011
Accepted: 3 May 2011
Published online: 18 August 2011
Thin films of a (Se80Te20)100−x Agx (1 ≤ x ≤ 4) were prepared by vacuum evaporation technique in a base pressure of 10−5 mbar onto well-cleaned glass substrates. The photoconductive measurements have been carried out on (Se80Te20)100−xAgx (1 ≤ x ≤ 4) thin films at different intensities 0–1200 lx in the temperature range 263–333 K. Dark conductivity (σd) and photoconductivity (σph) increase but the activation energy decreases as Ag concentration increases in the present glass composition. The measurements of intensity dependence of photoconductivity show that the photoconductivity increases with intensity as a power law where the power is found to be between 0.5 and 1.0. The photosensitivity (σph/σd) decreases with increase in Ag concentration. The results are explained on the basis of increase in the density of the localized states.
© EDP Sciences, 2011