High temperature variable-range hopping conductivity in undoped TiO2 thin film

Abstract

Electrical conductivity measurements in an undoped titanium dioxide thin film have been carried out as a function of temperature (180-320 K). The film has been deposited onto glass substrates by a d.c. magnetron-sputtering method, using water vapors as reactive gas. Analysis of the data showed that temperature dependence on the electrical conductivity was well described by the Mott type variable range hopping (VRH) law, suggesting that the density of states at the Fermi level is constant in this temperature range.