CHARACTERIZATION OF RF AND DC MAGNETRON REACTIVE SPUTTERED TiO 2 THIN FILMS FOR GAS SENSORS

摘要

This study presents the technology for prepudaring and characterization of titanium oxideudthin films with properudties suitable for gas sensors. Forudpreparing the samples the reactiveudradio frequency (RF) and direct current (DC) magnetron sputtering methods were used.udThe composition and microstructure of the films were studied by X-ray photoelectronudspectroscopy (XPS), X-ray diffudraction (XRD) and Raman spectroscopy, the surface of theudfilms was observed applying high-resolution scanning electron microscopy (SEM). Forudmeasuring the thickness and identifying the refractive indices of the films laserudellipsometry was used. The research was focuseudd on the sensing behavior of the sputteredudtitania thin films applying quartz crystal microbalance (QCM) method, which allowsuddetection of mass changes in the nanogram range. Prototype QCM sensors with TiOud2udthinudfilms were made by our team and tested for sensitivity to NHud3udand NOud2ud. These films evenudin as-deposited state and without heating thude substrates show good sensitivity. Additionaludthermal treatment is not necessary, making manufacturing of QCM gas sensor simple andudcost-effective, as it is fully compatible with the technology for producing the initialudresonator. The sorption is fully reversible and the studied TiOud2udfilms are stable, whichudmakes them capable for measudurements for long terms.