Preparation, characterization and gas sensor performance of nanocrystalline nickel-doped SnO2 films

In the present study, the effect of annealing temperature on structural, morphological, optical, and gas-sensing properties of the undoped and Ni-doped SnO2 films was thoroughly investigated by different identification methods. The XRD results indicate a tetragonal structure with (101) preferred orientation in all prepared films and the estimated crystallites size was found in the range of 15-29 nm that verified the formation of nanocrystals in the films. FESEM and AFM images reveal that the surface morphology of films is homogeneous with good adhesion to the substrate. The photoluminescence spectra of the samples show six prominent emission peaks centered at 373, 422, 461, 487, 530, and 600 nm. Additionally, all prepared films were evaluated for gas sensor applications at different operating temperatures and methanol gas concentrations. It was found that annealing temperature effectively influenced the sensor response of Ni-doped SnO2 based on methanol gas sensors. In addition, the best sensing response was observed at an annealing temperature of 500 & DEG;C. Finally, the sensor selectivity based on Ni-doped SnO2 annealed at 500 & DEG;C was tested for different gases.