Temperature-dependent electrical properties and impedance response of amorphous Ag _x (As₄₀S₃₀Se₃₀)_100−x chalcogenide glasses

Amorphous Ag _x (As₄₀S₃₀Se₃₀)_100−x (x = 1, 2, 3, 4 and 5 at.%) chalcogenide glassy alloys were prepared by a melt-quenching technique. DC conductivity data measured in the temperature range from 25 to 160 °C suggest that the dominant conduction mechanism is the thermally activated hopping of charge carriers between localized states in the band tails according to the Mott’s model. The activation energy of conduction for each sample was estimated on the basis of the Arrhenius law, indicating their semiconductor-like behavior. In frequency range from 100 Hz to 1 MHz, the analysis of the AC conductivity using the Jonscher’s universal power law showed that the correlated barrier hopping model is the most appropriate for explaining the AC conduction of all chalcogenide glasses in the present study. Moreover, detailed analysis of impedance spectra by means of an equivalent circuit model revealed the presence of temperature dependent electrical relaxation phenomenon of the non-Debye type as well as negative temperature coefficient of resistance behavior.