Quartz roughness affect on W03 coated QCM

Abstract

The influence of the initial quartz roughness on the WO3-QCM (Quartz Crystal Microbalance) parameters and sorption properties was investigated. Experiments were carried out using AT-cut quartz crystal with different surface roughness obtained after treatment with SiC abrasive having grain size of 3 μm, 7 μm, 14 μm and 20 μm respectively. The QCMs were covered with thin WO3 films. The equivalent dynamic parameters of the WO3- QCM were measured and a correlation with the surface roughness was determined. The equivalent dynamic resistance of the as-created QCM increases from 15.42 Ω to 117 Ω and the quality factor decreases as a result of the roughness changes. The surface morphology was observed by a Scanning Electron Microscopy (SEM), which showed higher increase of the WO 3 surface roughness compared to those of the initial quartz surface. The cross-section profiles of the investigated structures show different overlay of Au-electrodes. The sorption properties of WO3-QCM system to NH3 were studied in the range from 10 ppm to 1000 ppm. The response and recovering times were determined. The experimental results show an increase of the sorption ability with the increase of the initial quartz roughness. By increasing the roughness the mass-loading is improved. © 2010 IOP Publishing Ltd.