Ac conductivity and dielectric properties of Ga2S3-Ga2Se3 films

The ac conductivity and dielectric properties of amorphous Ga2S3-Ga2Se3 solid solution in thin film form have been studied in the temperature range from 306 to 403 K and in the frequency range from 10(2) to 10(5) Hz. The ac conductivity was found to be proportional to omega(s). The exponent S was found to be 0.997 at room temperature and decreased with increasing temperature. It was found also that ac activation energy Delta E(omega) has small values, which decreased with increasing frequency. It was found that relaxation time tau was 5.2 x 10(-5) s. These results were interpreted in terms of the correlated barrier-hopping model. It was found also that the dielectric constant E, and dielectric loss epsilon(2) decreased with the increase of frequency, while they decreased with increasing temperature in the investigated ranges. The calculated value of the barrier height W-m (0.485 eV) according to the Guintini equation agreed with that proposed by the theory of hopping of charge carriers over a potential barrier. (C) 2008 Elsevier B.V. All rights reserved.