The electrical conductivity of GexIn8Se92−x (14⩽x⩽25.5 at%) chalcogenide thin films

The dependence of the electrical conductivity (σ) on the composition, annealing time (ta) and temperature (T) in the range 80⩽T⩽475 K for the GexIn8Se92−x (14⩽x⩽25.5 at%) amorphous thin films has been investigated. The σ–T dependence for all the considered compositions has the same feature, which is that of semiconductor materials. Besides, at all temperatures the DC conductivity increases with increasing Ge:Se ratio. In addition, it has been observed that the conduction phenomena of the investigated thin films proceeded through two distinct mechanisms. The first one appears in the high-temperature region (T>430 K) and represents the thermally activated conduction through the extended states. The other, which appears in the low-temperature range (T<430 K), is less thermally activated and can be represented by the hopping conduction through the localized states. Finally, it can be decided that the annealing process inhibit the absolute values of the DC conductivity of the investigated compositions.