Photoconductivity in amorphous thin films of Ge22Se68Bi 10

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Abstract
Temperature and intensity dependence of steady state photoconductivity is studied in amorphous thin films of Ge22Se68Bi 10 prepared by vacuum evaporation. Photoconductivity increases exponentially with temperature between 310 K and 410 K and no maxima is found in this temperature range. The ratio Iph/ Id is about 6 at 310 K and decreases continuously as temperature is increased. Photoconductivity with intensity follows a power law where the power (γ) varies from 0.86 to 0.62 as the temperature is increased from 310 K to 380 K. Transient photoconductivity and thermally stimulated currents have also been measured on the same sample. A non-exponential decay of photoconductivity is observed which is very slow at room temperature in this material. A peak in TSC is observed at 365 K. The present measurements indicate the presence of continuous distribution of localized states in thin films of Ge22Se68Bi10