Effect of annealing temperature on structural and electrical properties of Al/Nb-doped TiO2 Schottky diodes on Pt–Si substrates

Abstract

The Nb-doped TiO2 (NTO) thin films were deposited on Pt-coated Si substrates for fabrication of Al/NTO Schottky diodes using RF magnetron sputtering technique. The effects of annealing temperature on the microstructure, surface morphological and electrical properties are systematically investigated. X-ray diffraction pattern shows that the crystallinity of NTO thin films can be improved by adjusting the annealing temperature. The surface morphological analysis shows that the grain size and roughness can be affected by the annealing temperature. According to I–V characteristics, the ideal factor, barrier height and series resistance of Al/NTO Schottky diodes calculated by various methods are consistent well. The ideal factor and series resistance decrease with annealing temperature rising from 200 to 600 °C. When the NTO thin films are annealed at 600 °C, the Al/NTO Schottky diodes have good rectifying behaviors with an ideal factor of 4.97, a Schottky barrier height of 1.04 eV and a relatively low series resistance of 235 Ω. These results indicate that the prepared Al/NTO Schottky diodes have potential application prospects in rectifying devices.