Obtaining of ZnO/Fe 2 O 3 Thin Nanostructured Films by AACVD for Detection of ppb-Concentrations of NO 2 as a Biomarker of Lung Infections.

ZnO/Fe 2 O 3 nanocomposites with different concentration and thickness of the Fe 2 O 3 layer were obtained by two-stage aerosol vapor deposition (AACVD). It was shown that the ZnO particles have a wurtzite structure with an average size of 51-66 nm, and the iron oxide particles on the ZnO surface have a hematite structure and an average size of 23-28 nm. According to EDX data, the iron content in the films was found to be 1.3-5.8 at.%. The optical properties of the obtained films were studied, and the optical band gap was found to be 3.16-3.26 eV. Gas-sensitive properties at 150-300 °C were studied using a wide group of analyte gases: CO, NH 3 , H 2 , CH 4 , C 6 H 6 , ethanol, acetone, and NO 2 . A high response to 100 ppm acetone and ethanol at 225-300 °C and a high and selective response to 300-2000 ppb NO 2 at 175 °C were established. The effect of humidity on the magnitude and shape of the signal obtained upon NO 2 detection was studied.