Characterisation of sol-gel prepared TiO2 thin film for O2 sensing

This paper presents the results of out-investigation on deposition and characterisation of soil-gel prepared TiO2 thin films for oxygen sensing applications. The properties of pure TiO2 thin films are compared with those doped with niobium oxide and 1%pt. These films are characterised using Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) to study their chemical composition, structure and surface morphology respectively. Both kinds of the films are stoichiometric. Pure TiO2 as well as doped films were amorphous as deposited. Pure TiO2 films after annealing to 450 degrees C and above showed the formation of anatase phase, while the doped films still predominantly amorphous, barely showing the onset of crystallinity. Pure films after annealing to 600 degrees C appear to have become granular and porous. Doping with niobium oxide anal Pt resulted in modification of film microstructure also. As a result of doping, the gas sensitivity of the films is increased from 8 to 24 and operating temperature decreased from 320 degrees C to 190 degrees C.