Investigation of a.c. conductivity measurements in a-Se80Te20 and a-Se80Te10M10 (M = Cd, in, Sb) alloys using correlated barrier hopping model

The a.c. conductivity of a-Se₈₀Te₂₀ and a-Se₈₀Te₁₀M₁₀ (M = Cd, In, Sb) alloys has been investigated as a function of temperature in the range from 280 to 330 K and frequency in the range from 10² to 10⁴ Hz. The experimental results indicate that a.c. conductivity σ_ac is proportional to ω^s where s < 1 and decreases with increasing temperature. The results obtained are discussed in terms of the correlated barrier hopping (CBH) model. An agreement between experimental and theoretical results suggests that the a.c. conductivity behavior of a-Se₈₀Te₂₀ and a-Se₈₀Te₁₀M₁₀ (M = Cd, In, Sb) system can be successfully explained by CBH model. The contribution of single polaron and bipolaron hopping to a.c. conductivity in present alloys is also studied.