a.c. Conductivity of Reactive-Evaporation-Deposited a-Si: H Films

The electrical-conductivity frequency dependence of reactiveevaporation-deposited a-Si:H films has been measured in the temperature range (100 + 450)K. The influence of the substrate temperature, of the hydrogen ions energy and of post-deposition thermal treatments has also been investigated. The results show that, depending on the material quality, three different conduction mechanisms associated with gap states, band or band tail states and to hopping processes near the Fermi level are observed