Preparation and room temperature methane sensing properties of platinum-decorated vanadium oxide films

• Pt/VOx films were prepared involving sputtering and rapid thermal annealing.
• A mixture of vanadium dioxide and vanadium pentoxide were synthesized.
• The Pt/VOx films methane sensor could operate at room temperature (∼25 °C).
• The optimal operating concentration was obtained at 1500 ppm toward methane.

Room temperature methane (CH4) response characteristics of vanadium oxide (VOx) thin films loaded with platinum (Pt) nanoparticles were investigated for detection of CH4. The Pt/VOx thin films have been prepared on sapphire substrate by means of dc-magnetron sputtering of V metal, followed by deposition of Pt nanoparticles, and then rapid thermal annealing (RTA) in O2 atmosphere from 450 °C to 470 °C. SEM and XRD were used to investigate the morphology and crystal structure of the films. The results showed that irregular rod-shaped particles with size on the average of 100 nanometers and the monoclinic vanadium dioxide (VO2) were obtained. The property of metal to insulator transition (MIT) was a confirmation of the prepared VO2. The sensor annealed at 460 °C showed the largest response value which was 18.2 toward methane (CH4) at room temperature with the concentration of 500 ppm. The optimal operating concentration for CH4 detection is 1500 ppm.

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