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 °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). H2 and C2H5OH gas sensing properties of the films calcined above 400 °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 H2 and C2H5OH gases regarding these CuO gas sensors are comparable to the values previously reported.