Low temperature HFCVD synthesis of tungsten oxide thin film for high response hydrogen gas sensor application

Abstract

• WO 3 thin films are obtained through low temperature HFCVD technique. • WO 3 thin films exhibits cauliflower morphology (WCNs) with typical monoclinic WO 3 crystal structure. • Highly uniform WCNs thin film is prepared. • High sensitivity of ∼87% towards H 2 gas is achieved. A quick and efficient approach was employed for the growth of nanocrystalline tungsten oxide (WO 3 ) thin films using one-step hot filament chemical vapor deposition (HFCVD) method at low temperature. In a typical experiment, the parent material tungsten (W) was subjected to oxidation, gasification and its subsequent condensation to obtain the uniform deposition of WO 3 thin film on silicon substrate at significantly low temperature of ∼200 °C. Prepared WO 3 thin film possessed the cauliflower nanostructure (WCNs) with typical monoclinic WO 3 crystal structure. Prepared WCNs thin films were applied for the detection of hydrogen (H 2 ) gas at 100 ppm. H 2 response increased with rise in temperature and the maximum response of ∼87% was obtained at the optimized temperature of ∼250 °C with response time 180 s.