Effect of sulfur doping on the dielectric properties of Sb 2 Se 3 system

Abstract

In this paper, we report the effect of sulfur doping on the electrical and dielectric properties of semiconducting Sb 2 Se 2 S over wide ranges of temperatures (298-473K) and frequencies (42-10 6 Hz). Sb 2 Se 2 S system has been prepared by the direct fusion and cooling cycle of a mixture of the constituent elements, in stoichiometric ratio and purity 99.999%, in vacuum-sealed silica tubes. X-ray analysis showed a decrease in the cell parameters a, b and c upon doping with sulfur. However, the pure and doped Sb 2 Se 3 showed the single orthorhombic phase structure. The permittivity of Sb 2 Se 2 S showed a decrease with increasing frequency due to a decrease in the average bond strength. While, ac conductivity increased with the frequency increase, obeying the Jonscher's universal dynamic law. The conductivity temperature dependence is well described by the correlated barrier hopping model. The activation energy calculated from DC conductivity is found at higher value (0.79eV) as compared to that reported in the literature for other antimony selenide compounds. Accordingly, a new Sb 2 Se 2 S compound is suggested which may be useful for electronic devices.