Novel hydrogen sensor based on p-type Ni:TiO_2 nanorods fabricated on ITO substrate

摘要

In the present work, Ni-doped TiO_2 nanorods were fabricated on indium tin oxide (ITO) coated glass substrate by a novel spray pyrolysis deposition route. The influence of pyrolytic temperature on the degree of crys-tallinity of the Ni:TiO_2 films was clearly reflected in the X-ray diffractograms. The promoting effect of ITO seed layer on Ni:TiO_2 film was reflected in the film prepared at 300 ℃ which show predominantly a (101) orientation corresponding to the c-axis of pure tetragonal anatase TiO_2. The evaluated optical band gap (E_g) of the films prepared at different temperature was in the range of 3.3-3.62 eV. The high E_g values confirmed the existence of TiO_2-Ni catalyst influence interaction. The morphology of the film optimized at 300 ℃ was almost rod shaped with large roughness favorable for sensing. The hydrogen sensing properties of the Ni:TiO_2 nanorod sensor was investigated. The Ni doped TiO_2 films exhibited a different p-type response to H_2. It was found that the sensor based on Ni:TiO_2 nanorod structure optimized at 300 ℃ exhibited good performance even at room temperature.