GAS SENSOR BASED ON TIN DIOXIDE-CARBON NANOTUBES NANOCOMPOSITE FILM FOR ISOBUTANE DETECTION

Semiconductive gas sensors based on tin dioxide-multiwalled carbon nanotubes (MWCNTs) nanocomposite film for isobutane detection in atmosphere are presented and discussed in this paper. Gas sensor design, construction and characterization are described. Combination of LTCC technology and thick-film technology was chosen for construction of heater which is placed into a TO 8 package. This solution ensures reaching the high operating temperatures needed to achieve the best sensitivity. Three types of differently MWCNTs loaded SnO2 based nanocomposite active films were deposited using spray-coating on a silicon substrate with an interdigitated structure. The first type was prepared from pure tin dioxide nanopowder only. Next two types of active layers were prepared as nanocompositions of tin dioxide nanopowder loaded with multiwalled carbon nanotubes (1.5 wt% and 3.0 wt%). All electrodes were tested in the gas chamber with changing concentration of isobutane in synthetic air. According to the obtained results it was found that the active layer with 3.0 wt% of multiwalled carbon nanotubes has the best sensitivity, response time and recovery time.