Post-deposition annealing effects on the transparent conducting properties of anatase Nb:TiO2 films on glass substrates

Five percent Nb-doped TiO2 (Nb:TiO2) films on glass substrates were prepared with pulsed laser deposition in 10 mTorr at room temperature, and then, they were annealed at various temperatures from 250 to 550 degrees C in vacuum (<10(-5) Torr). The X-ray diffraction data suggest that the as-prepared amorphous Nb:TiO2 film on glass was transformed to the (1 0 1) oriented anatase phase above similar to 350 C. For the anatase Nb:TiO2 samples, the temperature dependence of the resistance exhibited a metallic behavior. As the post-deposition annealing temperature increased up to 550 degrees C, the resistivity (similar to 3.9 x 10(-4) Omega cm) was minimum at 450 degrees C while the Hall mobility (2.6 cm(2)/(Vs)) and carrier density (4.7 x 10(21) cm(-3)) were maximum. The optical transmittance in the visible light range was about 70-80%, and the optical band gaps gradually decreased from 3.64 to 3.28 eV as the post-deposition annealing temperature increased. (C) 2013 Elsevier B.V. All rights reserved.