Optical and electrical properties of TiO2 doped with Tb and Pd

Optical and electrical properties of TiO2 doped with 0.6 at. % Tb and 9 at. % Pd have been investigated. Thin films were deposited by low pressure hot target reactive sputtering from a metallic Ti-Tb-Pd mosaic target on silicon and glass substrates. Total concentration of Tb and Pd was determined using an energy disperse spectrometer. Optical properties were studied by means of optical transmission. It has been shown that Tb dopant does not make any significant changes in the transmission level. Pd dopant shifts the fundamental absorption edge of TiO2 towards longer wavelengths and decreases the transmission to about 40%. For electrical characterization of the prepared thin films, temperature dependent resistivity and current-voltage (I-V) characteristics have been examined. It has been shown that incorporation of Pd and Tb into TiO2 matrix modifies its properties allowing one to obtain p-type oxide-semiconductor electrically and optically active at room temperature. Additionally, based on I-V measurements, the formation of heterojunction at the interface of thin film-silicon was confirmed.