Abstract
In this paper, the annealing effect of tungsten oxide (WO 3 ) nanoparticles has been studied on different Si and PS substrates by spin coating technology to develop the gas sensor. WO 3 thin film was prepared at RT, and 400 ∘ C. XRD pattern shows all films are polycrystalline in nature, and have hexagonal structure. The annealed of WO 3 thin film at 400 ∘ C showed high intensity crystalline peaks with decreased in crystal size. The fine nanoparticles are fully agglomerate and their spherical shape increases upon annealing of the film. The energy gap of WO 3 was 2.8 eV at RT, and it increased with increasing annealing temperature. The annealing temperature of 400 °C was selected and employed in gas sensors prepared on different substrates of Si and PS at RT, 100 °C, and 200 °C. The sensor was further fabricated to detect of nitrogen dioxide (NO 2 ) and ammonia (NH 3 ) gas at low concentration (8 ppm). The sensing effects toward NO 2 and NH 3 gases were compared between low- and high-temperature gases. The WO 3 /PS sample exhibited the highest sensitivity (144.1%) for NO 2 gas at 200 °C. The sensitivity of both gases showed different results with regard to the response. However, the response and recovery time of both gases were moderate and decreased with increasing operating temperature.
Published Version
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