Tungsten oxide thin film for room temperature nitrogen dioxide gas sensing

Abstract

Tungsten oxide (WO3) thin films for gas sensing have been successfully deposited using reactive direct current (DC) magnetron sputtering at different deposition temperatures (300 °C, 400 °C and 500 °C). The structural, morphological properties, thickness and composition have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rutherford backscattering spectrometry (RBS) techniques. To investigate the effect of deposition temperature on the gas sensing properties of deposited thin films on alumina substrates, was conducted using the Kenosistec gas sensing unit. WO3 thin film deposited at 500 °C exhibited a higher response when sensing Nitrogen dioxide (NO2) at room temperature as compared to the thin films prepared at 300 °C and 400 °C, respectively. However, as deposited WO3 thin films exhibited low sensitivity when sensing reducing gases such as hydrogen (H2) and ammonia (NH3), which was an indication of good selectivity properties of WO3 related sensors.

Optimisation of H‐doped WO3 synthesis at ambient conditions for potential acetone gas sensing

“…Recent trends in the field of biochemical engineering look into addressing the limitations by developing high‐performance gas sensors that can be operated at room temperature 11 . Despite lowered temperature demand, these sensors exhibited promising response towards target gases such as nitrogen dioxide, 12 hydrogen sulfide, 13 ammonia, 14 ethanol 15 and acetaldehyde 16 . In the context of acetone sensing at room temperature, Zhang et al 17 synthesised a zinc oxide nanopolyhedra/S, N: graphene quantum dots/polyaniline nanocomposite.…”

“…Many synthesis routes exist for the fabrication of WO 3 -based gas-sensing elements. Among these, commonly reported pathways include hydrothermal, 21,22 sol-gel, 23,24 sonochemical, 25 physical 12,26 or chemical vapour deposition 27 and electrospinning. 28,29 Typically, the selection of the right synthesis route depends on the desired surface morphology and composition.…”