1. Influence of annealing on gas sensing properties of WO3 thin films
- Author
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Paulina Kapuścik, Michał Mazur, and Damian Wojcieszak
- Subjects
electronics ,tungsten oxide ,thin film ,gas impulse magnetron sputtering ,gas sensing properties ,Technology - Abstract
Tungsten trioxide (WO3) is a wide-bandgap semiconductor. Its advantages include highchemical stability and low price. Furthermore, WO3 has chromogenic properties, that is, the abilityto switch between pale yellow and dark blue in response to various stimuli, including temperature,light irradiation, electric field, and exposure to hydrogen. Due to its high colouring efficiency andfast switching, it can be used in antidazzling mirrors and smart window applications, as well as in gassensing. In this paper, we present the influence of annealing on the properties of WO3 coatings that wereannealed at temperatures in the range from 200C to 400C. The sensing response was characterisedbased on the transmittance measurement during exposure to air and Ar/H2 mixture with hydrogenconcentrations from 25 ppm to 1000 ppm. Furthermore, the influence of annealing on the structureand morphology of the coatings was examined. Annealing at 400C led to a structure change fromamorphous to crystalline one. After the introduction of the Ar/H2 mixture, a decrease in transmittancewas observed for all of the analysed coatings. For films annealed at 200C and 300C, the transmittancevalue decreased during the entire colouring cycle, while for the coating annealed at 400C a plateau wasreached after 7 minutes of exposure. It was found that the best sensing characteristics were obtained forthe WO3 thin film annealed at 400C due to high sensor response to very low hydrogen concentrations(SR = 6.3 for 25 ppm H2) as well as short response and recovery times.Keywords: electronics, tungsten oxide, thin film, gas impulse magnetron sputtering, gas sensingproperties more...
- Published
- 2023
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