Investigations on Sn-doped Ni oxide thin films and their use as optical sensor devices

Tin-doped NiO thin films (5.0, 7.4, and 9.3 at.% Sn) have been prepared by thermal oxidation of vacuum deposited films of pure Ni and Sn elements on glass and silicon substrates. The prepared films were comprehensively characterised by X-ray fluorescence, X-ray diffraction, UV–VIS-NIR absorption spectroscopy, and electrical (ac and dc) measurements. Experimental data indicate that Sn4+ doping slightly stress the host NiO crystalline structure and change the optical and electrical properties. The electrical and optical behaviours of the Sn-doped NiO films show that they are wide-band semiconductors with band gap 3.69–3.76 eV and have insulating properties. The ac and dc electrical measurements show that it is possible to use Sn-doped NiO as an optical-sensitive oxide in metal-oxide-silicon configurations.