Enhanced ethanol sensing response of nanostructured Ce-doped CuO thin films

CuO based thin films doped with Ce concentrations varying from 0 to 8 mol% were prepared by chemical spray pyrolysis. X-ray diffraction analysis revealed bandgap modulation which is dependant on Ce doping and also showed perservation of the single phased monoclinic CuO structure for all the films after doping indicating successful substitution of Ce⁴⁺ ions in host matrix. SEM and AFM microscopy showed changes in morphology as Ce doping was increased. And this appeared to have a significant role on the ethanol sensing capabilities of the thin films which were measured at different working temperatures. Good gas sensing stability and maximum response was observed for the 4% Ce thin film. The sensing device was found to be more responsive towards ethanol than other common volatile organic compounds such as methanol, acentronile, ammonia and acetone. The response and recovery times for the sensing suggest a chemosorbption mechanism.