Abstract
The results are presented of a study of the electrical and optical properties of vacuum evaporated amorphous thin films in the Ge—S—Se system. The effect of Te isoelectronic substitution either completely for S to give Ge
2.5 Te
2.5 Se
95 and Ge
5 Te
5 Se
90 or partially for Se to yield Ge
2.5 S
2.5 Te
2.5 Se
92.5 and Ge
5 S
5 Te
5 Se
85 is discussed. The changes recorded for the electrical conductivity, the thermal activation energy and for the red shift of the absorption band edge are interpreted in terms of some physical properties such as connectedness, electronegativity, bond strength and atomic size. Correlation between the Tg and E
04 values for samples with the same average coordination number is also given.