Investigation of Electrical Properties and Complex Impedance Behavior of Chalcogenide Cu5Se75Ge10In10 Glass

摘要

Impedance spectroscopy has been used to investigate the electrical properties of Cu5Se75Ge10In10 chalcogenide glassy alloy over temperature range (304 K–374 K) and frequency range (1 Hz–1 MHz). This temperature range is chosenbelow the glass transition temperature. SEM and EDX measurements have been used for surface morphology and elemental analysis respectively. Impedance studies indicate the deviation from Debye-type relaxation and with rise in temperature the relaxation frequency deviates towards high frequencyside. The magnitude of Z′ decreases with increase in frequency indicating the increase in ac conductivity with rise in temperature. Z′ values for all temperatures merge at high frequency. This is due to release of space charge as a result of reduction in barrier propertiesof material with rise in temperature. Similar peak position of the impedance plots and normalized electrical modulus indicate the conduction in the glass and facilitating the long range migration of charge carriers. It has been observed that, studied chalcogenide glassy alloy exist in theform of molecular dipoles which are frozen at low temperature, as the temperature increases, the molecules become free to rotate and align themselves and show the dielectric dispersion in the radio frequency range. Decrease in ?′ and ?′′ with risein frequency indicating the improved optical quality of material which is significant for use in non-linear optical material applications. It has also been observed that conductivity as function of frequency has two components: dc conductivity and ac conductivity. The ac conductivity mechanismhas been inter- preted in terms of Correlated Barrier Hopping model (CBH) which confirms the transition from dc to dispersive behavior at higher frequency following the Jonscher universal power law as ～ωs (s < 1).