Effect of Zinc additive on dielectric properties of Cd-Se glassy system

Abstract

Cd5Se95-xZnx (x=0, 2, 4, 6) glassy alloy has been prepared by a melt-quenching technique. Thin films were deposited by thermal coating unit on ultraclean glass substrate under a vacuum of 10-6Torr. The absence of any sharp peaks in the X-ray diffraction confirms the amorphous nature of thin films. The frequency and temperature dependence of dielectric constant and dielectric loss in the frequency range of 1kHz to 1MHz and in the temperature range of 290-370K were studied. Dielectric dispersion was observed when Zinc (Zn) was incorporated into the Cd-Se system. The increase in dielectric parameter with Zn concentration may be due to increase in defect states. The DC conductivity has been reported to investigate the effect of Zn concentration on DC conduction loss. The results are interpreted in term of dipolar theory for Cd5Se95 and Cd5Se93Zn2 samples, while the remaining samples have been explained on the basis of DC conduction loss. It was also observed that the DC conductivity increased with the increase of Zinc concentration, which may be due to the decrease in the band gap near Fermi level.