ولی دلوجی

In this work, the electrical properties of carbon– nickel composite films deposited at different time (50–600 s) were investigated. The films were grown by radio frequency magnetron sputtering on glass substrates at room temperature. The electrical conductivity of the films was investigated in the temperature range of 15–500 K. The conductivity data in the temperature range of 400–500 K show the extended state conduction mechanism, while the multiphonon hopping (MPH) conduction is found to dominate the electrical transport in the temperature range of 150–300 K. The films deposited at 180 s have the maximum conductivity. The conductivity at T\60 K could be described in terms of variable range hopping (VRH) conduction. The localized state density around Fermi level (N(EF)) at low temperature for the films deposited at 180 s has the minimum value of about 4.02 9 1021 cm-3eV-1. The average hopping distance (Rhop) for the films deposited at 180 s has the maximum value of about 3.51 9 10-7 cm.