Thin chalcogenide films of GexFex Se100-2x (x= 2.5,5,10 and 15 at.%) with thickness about ≈ 300 nm, have been prepared by thermal evaporation technique. A.C. conductivity σa.c. (ω) of the prepared thin films has been measured in the frequency range (0.1-20 K Hz), over the temperature range(300-345 K).Obtained data reveal that σa.c. (ω) obey the relation, σa.c. (ω)= Aωs ,and the exponent, s, was found to decrease by increasing temperature. The values of, s, of the investigated thin films lie between 0.4 to 0.9. The data were analyzed in terms of different models of a.c. conduction. It was found that, the correlated barrier hopping (C.B.H.) is the dominant conduction mechanism. The dependence of dielectric constant έ and loss factor (tan δ) on both frequency and temperature has been also treated.
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