Structural, electrical and optical properties of sputter-deposited Nb-doped TiO2 (TNO) polycrystalline films

Transparent conductive oxide (TCO) films of polycrystalline Nb-doped TiO2 (TNO) were fabricated by post-annealing reactively sputtered amorphous films under H2 atmosphere. Carrier transport properties of the H2-annealed films were found to be strongly dependent on substrate temperature Ts and oxygen content in sputtering atmosphere. A minimum resistivity (ρ) of 9.5 × 10− 4 Ω cm and an average visible transmittance of ∼ 75% were obtained at Ts = RT and oxygen content of 10%. This ρ value is of the same order as those of epitaxial TNO films, indicating that polycrystalline TNO has sufficient potential as a practical TCO suitable for large-area applications.