Enhanced Room Temperature Ammonia Gas Sensing Response of DC Magnetron Sputtered Vanadium Oxide Thin Films

Abstract

Abstract: In this study, the sensitive selective ammonia (NH₃) gas sensor was fabricated using V₂O₅ thin films synthesized by DC (direct current) magnetron sputtering technique with different substrate temperatures. The sputtered V₂O₅ thin films were analyzed for their optical, structural, morphological, and gas-sensing properties. X-ray diffraction (XRD) and Raman spectroscopy results indicated that the thin films were amorphous. The gas-sensing performance was evaluated at various substrate temperatures and different  NH₃ concentrations ranging from 5 to 200 ppm, with 27 °C as the operating temperature. The V₂O₅ thin films achieved their maximum response to NH₃ at room temperature (27°) and an optimal ammonia concentration of 100 ppm. Notably, the room-temperature-sputtered V₂O₅ sensors showed a good gas-sensing response of 45.94%. After 50 days, the gas response to the same NH₃ concentration was nearly 44.23%. Furthermore, all sputtered gas sensors demonstrated good selectivity toward NH₃ over other gases, including acetone, methanol, ethanol, and toluene, as well as long-term stability.

Keywords: Sputtering, Gas sensing response, Operating temperature, Sensitivity, Selectivity.