6th International Conference of the Balkan-Physical-Union, İstanbul, Türkiye, 22 - 26 Ağustos 2006, cilt.899, ss.588
D.c. and a.c. conductivity measurements have been performed on unannealed amorphous As0.40Se0.40Te0.20 thin films. The d.c. behaviour of the samples indicates hopping conduction mechanisms between 143K-210K and 210K-343K. The a.c. conductivity of the films is well represented by the form C omega(s) where C and s are found to be temperature dependent parameters. The data are found to fit the correlated barrier hopping (CBH) model, especially at low temperatures. The comparison of a.c. data with the unified theory of the extended pair approximation (EPA) shows that the results fit to the quasi universal law predicted by this model, however, qualitative calculations give unreasonable values for the decay parameter alpha and the exponent l.