Sputtered NiO thin films for organic vapours testing

NiO thin films were prepared by dc reactive magnetron sputtering with thicknesses of about 50 and 100 nm on alumina and KCl substrates. The deposited films were annealed in a furnace at 500°C in nitrogen atmosphere for 2 hours. From XRD and TEM investigations were found that annealed NiO thin films have a polycrystalline structure with the size of grains below 25 nm. The electrical responses of NiO sensor structures towards different ethanol, acetone and toluene concentrations have been measured. It was found that the thickness of NiO films is an important parameter in determining the sensitivity of prepared gas sensors.