Preparation of ZnO nanostructures by RF-magnetron sputtering on thermally oxidized porous silicon substrate for VOC sensing application

•Porous structures were introduced to ZnO by using a thermally oxidized PS.•The sensitivity of the ZnO/oxidized PS was 83.4% for 22 ppm of ethanol gases.•High porosity, and abundant oxygen vacancies enhanced the sensing.•The sensor showed favorable selectivity for ethanol over acetone.

ZnO nanostructures were grown on thermally oxidized porous silicon (PS) substrates by RF-magnetron sputtering for volatile organic compounds (VOCs) sensing applications. PS was fabricated by electrochemical anodization of n-type crystalline silicon in an ethanoic hydrofluoric acid solution to produce a PS surface. X-ray diffraction (XRD) analysis confirmed that the ZnO nanostructure highly preferred an (0 0 2) phase orientation. The sensitivities of the ZnO/oxidized PS sensor investigated for 22 ppm of acetone, ethanol, iso-propanol, and toluene vapor at the optimum operating temperature of 250 °C were 79.6%, 83.4%, 69.3%, and 69%, respectively. The ZnO/oxidized PS sensor can be detect VOC vapor up to 2 ppm.

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