Low temperature electric transport properties in hydrogenated microcrystalline silicon films

The dark conductivity of microcrystalline silicon (μc-Si:H) films, deposited in a RF-PECVD system varying the RF power in the 15-100 W range, has been investigated as a function of the temperature. Under low electric field condition (103 V/cm), the conductivity of the samples as a function of the exponential of T− 1/4 presents a linear behaviour in the measured temperature range. The density of states near the Fermi level, the range of hopping and the activation energy for hopping have been evaluated using the diffusion model. A correlation between the hopping parameters and the crystallinity degree has been found.