Characterisation of Nanostructured SnO 2 Thin Films Synthesised by Magnetron Sputtering and Application in a Carbon Monoxide Gas Sensor

Tin oxide (SnO₂) thin films were deposited onto glass substrates using DC magnetron sputtering system as a CO gas sensor. The dependence of the deposition time on structural, morphological and CO gas sensing properties of SnO₂ thin films were investigated. The synthesised SnO₂ thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and surface profiler. Also the CO gas sensing properties of SnO₂-deposited thin films were performed against a wide range of concentration of CO gas. XRD analysis demonstrated that the degree of crystallinity of the deposited SnO₂ thin films strongly depended on the deposition time. Also, SEM and AFM analyses revealed that the size of nanoparticles/agglomerates, and both average and rms surface roughness were enhance with increasing the deposition time. Gas sensors based on these SnO₂ nanolayers showed an acceptable response to CO at various concentrations. Also it has been demonstrated that SnO₂ sensors are highly suitable for sensing CO gas at comparatively lower operating temperatures.