Paper SE-ThP6
Hard Transparent Conducting Nb-doped Titania Films by Reactive Co-Sputtering

Thursday, October 23, 2008, 6:00 pm, Room Hall D

The outstanding properties of titania have made them useful for many applications including photocatalysis, gas sensors, dielectric thin-film capacitors and solar cells. However, researchers have not paid much attention to their transport properties and mechanical behaviors. We have produced a series of niobium-doped titania films by reactive co-sputtering titanium and niobium targets and by subsequent annealing the films in a hydrogen environment. The composition of the films was modulated by changing the niobium target power; consequently, niobium content of the films changed from 0 to 4.2 atomic percent. The characterization studies show that the annealed films are polycrystalline with anatase phase without accompanying other crystalline oxide phases. The results also demonstrate that the films possess high visible-light transparency as well as enhanced hardness and conductivity. For instance, the doped titania film of 2.8 at% Nb deposited at a substrate temperature of 350 °C and annealed at 600°C exhibits an average transmittance of 70% in visible light region and a high hardness up to 11.4 GPa. Moreover, the Hall measurements of the film reveal n-type semiconducting behavior for this film with a reduced resistivity of 9.2E-4 ohm-cm, a carrier density of 6.61E21 cm^-3 and a mobility of 1.0 cm²v^-1s^-1.