Investigation of Fe-doped and -undoped NiO nanocrystalline films

The NiO and Fe-doped NiO thin films have been prepared by using spray pyrolysis technique. The effects of change in the volumetric concentration and substrate temperature on the film characteristics have been investigated. With the increase in volumetric concentration, the grain size and the roughness of the film increase; while the number of voids has been reduced. In case of NiO thin films the activation energy was found to increase from 0.33 eV to 0.40 eV with the increase in the film thickness. The analysis of the data suggests that the density of states at the Fermi level increase with the thickness of the film. In Fe-doped NiO film the density of states was found to increase with the increase in the substrate temperature. The optical measurements show that the maximum transmittance (approximate to 77.13%) occurs for the film corresponding to the lowest volumetric concentration. On increasing the substrate temperature the transmittance also increases, thus displaying the decrease in the film thickness.