Characterization of niobium-doped titania epitaxial films deposited by metalorganic chemical vapor deposition

Titania (TiO2) films with different niobium (Nb) doping concentrations were deposited on SrTiO3 (STO) (100) substrates by metalorganic chemical vapor deposition (MOCVD). The crystal structures, surface morphologies, electrical and optical properties of the Nb-doped TiO2 (TiO2:Nb) films varying with Nb content were investigated. The single crystal TiO2 films with anatase structure were obtained at low Nb doping levels. The highest Hall mobility of the prepared films reached as high as 16.50 cm2 V−1 s−1. The lowest resistivity of 5.75 × 10−2 Ω cm with a Hall mobility of 7.40 cm2 V−1 s−1 and a carrier concentration of 1.47 × 1019 cm−3 were obtained from the 1.20% Nb-doped TiO2 film. This resistivity was about 6 orders of magnitude lower than the undoped TiO2 film. Moreover, all the deposited films exhibited high average transmittances of over 88% in the visible wavelength range.