Evidence of quantum correction to conductivity and variable range hopping conduction in nano-crystalline Cu<inf>3</inf>N thin film

We have investigated the temperature dependent carrier transport properties of nano-crystalline copper nitride thin films synthesized by modified activated reactive evaporation. The films, prepared in a Cu-rich growth condition are found to be highly disordered and the carrier transport in these films is mainly attributed to the impurity band conduction. We have observed that no single conduction mechanism is appropriate to elucidate the carrier transport in the entire temperature range of 20 - 300 K. Therefore, we have employed different conduction mechanisms in different temperature regimes. The carrier transport of the films in the low temperature regime (20 - 150 K) has been interpreted by implementing quantum correction to the conductivity. In the high temperature regime (200 - 300 K), the conduction mechanism has been successfully analyzed on the basis of Mott's variable range hopping mechanism. Furthermore, it can be predicted that copper ions present at the surface of the crystallites are responsible for the hopping conduction mechanism.