Fabrication of highly conductive Ta-doped SnO₂ polycrystalline films on glass using seed-layer technique by pulse laser deposition

We discuss the fabrication of highly conductive Ta-doped SnO₂ (Sn_{1 - x}Ta_xO₂; TTO) thin films on glass by pulse laser deposition. On the basis of the comparison of X-ray diffraction patterns and resistivity (ρ) values between epitaxial films and polycrystalline films deposited on bare glass, we proposed the use of seed-layers for improving the conductivity of the TTO polycrystalline films. We investigated the use of rutile TiO₂ and NbO₂ as seed-layers; these are isostructural materials of SnO_2, which are expected to promote epitaxial-like growth of the TTO films. The films prepared on the 10-nm-thick seed-layers exhibited preferential growth of the TTO (110) plane. The TTO film with x = 0.05 on rutile TiO₂ exhibited ρ = 3.5 × 10^{- 4} Ω cm, which is similar to those of the epitaxial films grown on Al₂O₃ (0001).