INFLUENCE OF AACVD TEMPERATURE ON THE MICROSTRUCTURAL AND GAS SENSING PROPERTIES OF ZnO THIN FILMS

Thin films of zinc oxide were obtained by the AACVD method. The variable parameter was the synthesis temperature, which was from 350 to 500°C with a step of 25 degrees. The analysis revealed that ZnO particles have a wurtzite structure with an average crystallite size of 26 ± 4 nm. As a result of the analysis of the morphology of the obtained films, it was shown that in the temperature range from 400–450°C, continuous films with an average particle size of 52 ± 14 nm are formed, and at synthesis temperatures of 350–375°C; 475–500°C, films with a discontinuous island-like morphology with an average size of 51 ± 13 nm are formed. The optical properties of the obtained films were studied, and the estimated values of the band gap were 3.31–3.34 eV. A temperature-dependent mechanism of film formation was proposed. The chemosensory properties were studied at an operating temperature of 150–350°C using a wide range of analyte gases: CO, NH, H, CH, CH, ethanol, acetone and NO₂. The thin films showed high sensitivity (4–100 ppm) to volatile oxygen-containing organic compounds (acetone and ethanol) at an operating temperature of 350°C. The effect of humidity on the magnitude and shape of the signal obtained during acetone detection was studied.