An optical-absorption study of synthetic RuS2-xSex single crystals is reported over a temperature range from 80 to 300 K. The data are fitted to several expressions for the shape of the absorption edge, with the best fit being to that expected for indirect allowed transitions. The band gaps at any temperature varies smoothly with the Se composition x, indicating that the nature of the band edges are similar for RuS2, RuSe2, and the compounds of intermediate compositions. The indirect band gaps of various temperatures are determined and their temperature dependence are analyzed by the Varshni equation [Physica 34, 149 (1967)] and an empirical expression proposed by O'Donnell and Chen [Appl. Phys. Lett. 58, 2924 (1991)]. The parameters that describe the temperature dependence of energy gap of RuS2-xSex are evaluated and discussed.
ASJC Scopus subject areas
- Physics and Astronomy(all)