Electrical properties of nanocrystalline TiO2 thin films doped with Tb and Pd

Transparent Oxide Semiconductors based on nanocrystalline thin films with desirable electrical and optical properties, are important in applications for transparent electronics. Such thin films can be applied, among others, as active layers in transparent transistors, UV photodiodes or solar cells. In this article, the presented subject of research are the thin films based on TiO2 doped with Tb and Pd. The thin films were deposited on glass and silicon substrates by the magnetron sputtering method. Structure of the TiO2:(Tb,Pd) thin films was investigated by the X-ray powder diffraction. Electrical measurements allowed the analysis of conduction mechanisms in fabricated thin films. From thermoelectrical characteristics conductivity, a type of electrical conduction, the activation energy and the Seebeck coefficient were determined. On the basis of current to voltage characteristics the power dependence I∼Um was found for structures consisted of the thin films deposited on silicon. This behaviour indicates a conduction mechanism known as (SCLC). Additionally, from the temperature dependence of the current density, the trap concentration and the characteristic temperature were estimated.