Conduction and dielectric polarization in Se thin films

Abstract

Se films were prepared by thermal evaporation technique in thickness range 150-8500 Angstrom. X-ray diffraction measurements showed that Se films are in the amorphous state. The ac conductivity and dielectric properties of the amorphous Se films have been investigated in the frequency range 100-100 KHz and 100-400 K temperature range. The ac conductivity sigma(ac)(omega) is found to be proportional to omega(s) where s < 1. The temperature dependence of both ac conductivity and the parameter s is reasonably well interpreted by the correlated barrier (CBH) model. The dc conductivity at the room temperature was also studied in the same thickness range. It was concluded that the same mechanism of carrier motion might be dominant in both ac polarization and dc conduction. This carrier transport mechanism might be electronic. (C) 2003 Elsevier Ltd. All rights reserved.