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

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.