H2 and C2H5OH sensing characteristics of mesoporous p-type CuO films prepared via a novel precursor-based ink solution route

The p-type semiconducting CuO mesoporous films were fabricated with a novel ink solution formulated optimally with an organometallic precursor and a polymer additive. The films were calcined at 200-600 degrees C in air and their crystallinity, morphology, pore structure and chemical composition were investigated by X-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM) and X-ray photoelectron spectroscopy (XPS). H-2 and C2H5OH gas sensing properties of the films calcined above 400 degrees C were investigated as a function of operating temperature, and were correlated with crystallinity, hole concentration and morphological factors of each film. The calcination-temperature dependence of the p-type gas sensing properties regarding the films suggested that higher hole concentration/crystallinity/surface-to-volume ratio and better crystallinity/lower grain boundary density in the sensing films lead to higher and faster p-type gas responses, respectively. In addition, to the best of our knowledge, the responses toward H-2 and C2H5OH gases regarding these CuO gas sensors are comparable to the values previously reported. (c) 2012 Elsevier B.V. All rights reserved.