Chandrabhan Dohare

Abstract:

A detailed study of conduction mechanism of glassy Se70Te28M2 (M=Ag, Cd, Zn) systems has been carried out in terms of dielectric and a.c. conductivity. Temperature and frequency dependent dielectric, loss tangent and a.c. conductivity for the same systems were measured in the frequency spectrum, 1 KHz -1 MHz and temperature, 303-338K range. The a.c. conductivity, i³ac is found to be proportional to (where, s < 1). The temperature dependence of both a.c. conductivity and frequency exponent 's' is reasonably well interpreted by the correlated barrier hopping (CBH) model. We showed that the bi-polaron hopping is dominant over the potential barrier and estimated the density of defect states (DOS) at 50 KHz. We found a good agreement in fitting of data (single and bi-polaron conductivity) with experimental results. Surface and structural morphology of as-prepared semiconducting glasses were confirmed by XRD, SEM and TEM. Glass kinetics (glass transition and crystallization) was interpreted by differential scanning calorimetry (DSC).