Resistive low-temperature sensor based on the SiO2ZrO2 film for detection of high concentrations of NO2 gas

Abstract

The SiO2ZrO2 composite films were prepared by means of sol-gel technology and characterized by scanning electron microscopy, energy dispersive X-ray (EDX) analysis, and X-ray diffraction. The presence of the stable monoclinic ZrO2 with an impurity of tetragonal phases is shown. The film surface is characterized by the presence of ZrOCl2±6H2O or ZrCl(OH)/ZrCl(OH)2 grains. The crystallite size negligibly depends on the annealing temperature of the film and amount to 10-12 nm and 9-12 nm for the films thermally treated at 200 °C and 500 °C, respectively. The film's resistance is rather sensitive to the presence ofNO2 impurities in the air at a low operating temperature (25 °C). Accelerated stability tests of the initial resistance showed high stability and reproducibility of the sensor based on the SiO2ZrO2 film thermally treated at 500 °C.