Ethanol sensing behaviour of CuMnO2 nanostructured thin films
Copper manganese oxide nanostructures were spray pyrolytically deposited on glass substrates with Cu:Mn concentrations 0.05:0.05, 0.1:0.1, 0.15:0.15, 0.2:0.2 M at the substrate temperature of 300 °C. The peak positions of the films deposited with precursor concentration 0.15:0.15 M confirmed the monoclinic CuMnO2 single phase structure. Surface morphology of the films was analyzed and then the chemical environment about the presence of Cu, Mn and O was analyzed in a photoelectron spectrometer. The binding energies of Cu-2p doublet positioned at 932.5 and 952 eV, represented the existence of Cu1+ in the films. Additional peak located at binding energies 638.8 and 650.3 eV corresponds to the Mn-2p of the film. The direct band gaps of the film were estimated and found near to 3.7 eV. The room temperature electrical conductivity of the film was 0.5577 mho/cm, which was comparatively high in the ABO2 group of compounds. The ethanol gas sensing property of the CuMnO2 films were measured at RT, 100 and 200 °C temperatures and the sensitivity was analysed and compared.