Effects of Thermal Annealing on Ti/Au Contacts to Anatase TiO2 Nanocrystal Films Prepared by Sol–Gel Method

Abstract

The electrical properties of Ti/Au contacts to anatase TiO2 nanocrystal films are investigated under different thermal annealing temperature (300–500 °C) in a N2 ambient. The as-deposited contact shows a non-linear current–voltage (I – V) property. However, after being annealed at 300 °C and 400 °C, the samples exhibit nearly ohmic I – V behaviors with currents at 5 V bias higher than that of as-deposited one by about three and seven times, respectively. When the annealing temperature is increased to 500 °C, the ohmic contact transform to Schottky contact. The influence of annealing temperatures on Ti/Au contacts to anatase TiO2 nanocrystal films depends on the interdiffusion behavior between the electrode layers and TiO2 films, which was investigated by Auger electron spectroscopy. Possible mechanisms are proposed to explain the influence of annealing temperature on the electrical properties of Ti/Au contacts to anatase TiO2 nanocrystal films.