Ac Conductivity of Amorphous As₂Se₃

Abstract

Electrical conduction in amorphous As 2 Se 3 is investigated at frequencies from 30 Hz to 10.3 GHz in the temperature range -180° to 500°C. The observed conductivity σ can be expressed as a sum of dc conductivity σ dc and ac conductivity σ ac , namely σ=σ dc +σ ac . The quantity σ dc depends exponentially on reciprocal temperature. The contribution of σ ac to σ is negligible at high temperature. At low temperature, σ ac is nearly independent of temperature but strongly depends on the frequency. The frequency dependence of σ ac is linear and quadratic in the frequency range up to 10 6 Hz and between 10 6 and 10 8 Hz, respectively, and above 10 8 Hz, σ ac has no frequency dependence. The experimental results of the conductivity of amorphous As 2 Se 3 cannot be interpreted by the hopping conduction only, and the effects of spatial inhomogeneity may be responsible for the conduction mechanisms in amorphous As 2 Se 3 .