Composition Dependence of Photoconductivity in Amorphous Thin Films of Se.80-xTe.20Gex

Authors : D KUMAR, S KUMAR

Pages : 91-96

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The present paper reports the dependence on composition of photoconductivity in vacuum evaporated thin films of amorphous Se.80-xTe.20Gex insert ignore into journalissuearticles values(x = .05, .10, .15 and .20);. Temperature dependence of conductivity in dark as well as in presence of light show that conduction is through a thermally activated process in both cases. The activation energy is found to decrease with increase in light intensity, indicating shift of the Fermi level with intensity. A correlation between activation energy and the pre-exponential factor is observed in all the compositions, which could be fitted to the Meyer-Neldel rule. Measurements on the dependence of photoconductivity on intensity show that photoconductivity increases with intensity as a power law, where the power is found to be between 0.5 and 1.0. The photosensitivity sph/sd increases with Ge concentration. This is explained in terms of the decrease in the density of defect states with increase of Ge content in a-Se.80-xTe.20Gex. This is consistent with the conclusions reported in the literature by dielectric loss measurements.
Keywords : Chalcogenide Glasses, Photoconductivity, Amorphous Thin films