Investigation of electrical conductivity (AC/DC) and dielectric properties of Se80Te15−xCd5Bix (x = 0, 5, 10) quaternary chalcogenide glass

This work reports the studies of AC and DC conduction in bismuth doped quaternary chalcogenide glass Se80Te15−xCd5Bix (x = 0, 5, 10). Dependence of AC conductivity (σac), dielectric constant (ϵ′) and dielectric loss (ϵ″) of glasses prepared by melt quenching technique was investigated for 100 kHz–1 MHz frequency range and 294–351 K temperature range. An increment in the values of DC and AC conductivities was observed with the addition of bismuth. Dielectric parameters were found to increase with the increase in temperature however a Decrease in the values of ϵ′ and ϵ″ was observed with the increase in frequency. Temperature dependence of σdc portrayed non-linear nature and was studied for the lower (294–317 K) and intermediate (317–351 K) temperature ranges. Values of hopping distance (Rhop) and hopping energy (Whop) suggested the use of Mott’s model to interpret the σdc data for lower temperature range. DC conduction in intermediate temperature range was interpreted by Greave’s model. The density of localised states [N(EF)] was estimated using σac and σdc data for the prepared glasses and has been found to be dependent on extent of bismuth doping. In last, an attempt to correlate the structural and phase change properties of the sample on the basis of electrical measurements were made and it was found that bismuth incorporation in chalcogenide glasses tunes the material for application in phase change memory devices.