Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 69: Emerging oxide semiconductors II (Focus session with DS)
HL 69.6: Talk
Wednesday, April 2, 2014, 16:30–16:45, POT 081
Structural and electrical properties of Nb doped TiO2 anatase films (2 - 17 at.%) sputtered with plasma emission control — •Sebastian Schipporeit1, Sanat Kumar Mukherjee1, Hans-Werner Becker2, Andrew Paolo Cádiz Bedini1, Christian Notthoff1, Abdelkader Nebatti1, Detlef Rogalla1, Azadeh Soleimani-Estafani1, and Dieter Mergel1 — 1Thin Film Technology Group, Faculty of Physics, University Duisburg-Essen — 2University Bochum
Nb doped TiO2 films were deposited using radio frequency magnetron sputtering with a metallic Ti target and introducing O2 and Ar gas into the chamber. Nb wires were put onto the sputter track of the Ti target and the oxidation state of the target was controlled using a Ti line of the plasma emission. The films were analysed with XRD, RBS, SEM, EDX and XPS. After annealing at 400 ∘C, all films are polycrystalline and inhibit anatase structure. The Nb/(Nb+Ti) content varies from 2 to 17 at.%. The lattice parameter a and the unit cell volume increase in a similar manner compared to TiO2:Nb single crystals.
The films with the lowest resistivity of 7·10−4 Ωcm (Nb content: 10 at.%) were coated with an oxidation state of the target in the transition region between metallic and oxidic modes. The Nb is incorporated as Nb5+ into the anatase lattice. In films with higher resistivity, the donor effect of Nb might be compensated by Ti vacancies (acceptors). The oxygen content is higher than in stoichiometric TiO2. Ogyxen interstitials might increase the mass density in the films.