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.