Fabrication and characterization of ZnO thin film for hydrogen gas sensing prepared by RF-magnetron sputtering

A ZnO thin film-based gas sensor was fabricated using a SiO2/Si substrate with an integrated platinum comb-like electrode and heating element. The structural characteristics, morphology, and surface roughness of the as-grown ZnO nanostructure were investigated. The optical properties were examined by UV–vis spectrophotometry. The film revealed the presence of a c-axis oriented (0 0 2) phase of 20.8 nm grain size. The sensor response was tested for hydrogen concentrations of 50, 70, 100, 200, 400, and 500 ppm at operating temperatures ranging from 250 °C to 400 °C. The sensitivity toward 50 and 200 ppm of hydrogen at the optimum operating temperature of 350 °C were about 78% and 98%, respectively. The response was linear within the range of 50–200 ppm of hydrogen concentration. Our results demonstrated the potential application of ZnO nanostructure for fabricating cost-effective and high-performance gas sensors.

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► A ZnO film-based gas sensor was fabricated with integrated Pt heating element.
► The Pt was found to have longer life time with a SiO2 coverage layer.
► The sensitivity towards 200 ppm of hydrogen gas at 350 °C was about 98%.
► The ZnO gas sensor exhibited excellent stability.