Preparation of Ge−Se−Sb ternary alloys and study of the effect of antimony on electrical properties, extended and localized energy states

The composition dependence of electrical properties, density of states (N(E), activation energy and electric parameters of Ge30-xSe70Sbx (x = 0, 10, 20 and 30) chalcogenide glasses is investigated. The DC-voltage and electrical conductivity characteristics of chalcogenide glass samples with diameter of 15 mm and thickness of 2.5 mm prepared under a constant load of 7 Ton were studied using the bulk melt-quenching technique as a function of composition. The I-V characteristics were recorded at room temperature and then heated to temperatures as high as 300 °C. Experimental data indicates that glass containing 20% Sb has minimal resistance allowing maximum current through the sample compared to other series counterparts. Therefore, the DC conductivity was found to increase with increasing Sb concentration. The dependence on the formation of DC conductivity concentrations of the chemical elements constituting the samples was discussed. Electrical conductivity measurements revealed the presence of three conduction mechanisms dependent on temperature ranges: at elevated temperatures from (400 to 465) K, conductivity would be between levels of extended states. As for the average temperatures from 350 to 400 K, it is between the local states of the tails of the states, while at the low temperatures 280-350, the conductivity occurs between the states associated with the Fermi level. The effect of partial substitution of germanium with antimony produced a change in all electrical conductivity parameters including the tails of the localized states and densities of states (extended, localized, and Fermi), activation energy (ΔE1, ΔE2 and ΔE3), tail width (ΔE), hope distance (R), and interatomic distances (a).