Effect of sputtering power on the methane sensing properties of nanostructured cadmium oxide films

Abstract

Effect of sputtering power on properties of CdO thin film deposited on glass substrate at room temperature by reactive dc magnetron sputtering has been studied. Correlation between the crystal structure, morphological and optical properties were systematically investigated. It has been found that sputtering power increases the crystallographic orientation of the film and at highest sputtering power, deterioration in crystallite growth occurs due to the excessively energetic sputtered particles. The microstructure of the films changes from nano flakes to self-assembled nano-pillar like structure with increasing sputtering power. All the films were highly transparent. The resistivity of the film decreased with increasing sputtering power and at 50W, it increased to 16×10−2Ωcm due to higher ion bombardment effects. The methane sensing properties has been demonstrated with the fabricated CdO based sensor at a relatively low operating temperature.