The effect of the Sb content on the physical properties of amorphous Se 0.75Ge 0.25− y thin films

Abstract

The effect of the addition of varying amounts of antimony in concentrations from 0.01 to 0.20 at% to Se 0.75Ge 0.25- y glass on its dc conductivity is analysed. The electrical conductivity of amorphous thin films of vacuum evaporated Se 0.75Ge 0.25- y Sb y were determined during and after light exposure and at different temperatures. The time dependence of the electrical conductivity measured in darkness or when exposed to light at about room temperature has been studied for amorphous Se 0.75Ge 0.25- y Sb y ( y=0.01, 0.05, 0.10, 0.15, 0.18 and 0.20) thin films of different compositions and different thicknesses. The conduction activation energy Δ E and the pre-exponential factor σ 0 (0, T) which appear in the dc conductivities are found to decrease with increasing Sb content. The mean value of the threshold voltage, was measured either in darkness, V ̄ th , and after exposure of light V ̄ th il , for different compositions and temperatures. The pronounced glass-forming tendencies of alloys of Se and Ge with Sb were discussed topologically in terms of the chemical bonds expected to be present in these materials. These chemical bonds have been used to estimate the cohesive energies (CE) of the glasses.