Electrical Conduction in Cluster Assembled Carbon Films Produced from a Supersonic Beam

We present a study on electricalconduction in nanostructured carbonfilmsproduced by deposition of asupersonicbeam of neutral carbonclusters. The electrical transport properties have been investigated by measuring the electrical conductance both in-situ, during the film deposition, and ex-situ, after the film exposure to ambient air. The I–V characteristic indicates a strict ohmic behavior all over the measured electric field range up to (2 kV/cm). Changes in the electrical conductance have been observed due to gas adsorption-desorption mechanisms. The exposure to air leads to a passivation of the film with an increase of resistivity up to ∼0.1 GΩ·cm. Current-temperature characteristics measured in vacuum in the temperature range 150–400 K, both in-situ and ex-situ, indicate a thermally activated conductivity with energy of ∼0.3 eV.