Gas sensors based on the multi-sensor platform MSP 632, with thin nanocomposite films based on tin dioxide with a low content of zinc oxide (0.5–5 mol.%), were synthesized using a solid-phase low-temperature pyrolysis technique. The resulting gas-sensitive ZnO-SnO₂ films were comprehensively studied by atomic force microscopy, Kelvin probe force microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. The obtained films are up to 200 nm thick and consist of ZnO-SnO₂ nanocomposites, with ZnO and SnO₂ crystallite sizes of 4–30 nm. Measurements of ZnO-SnO₂ films containing 0.5 mol.% ZnO showed the existence of large values of surface potential, up to 1800 mV, leading to the formation of a strong surface electric field with a strength of up to 2 × 10⁷ V/cm. The presence of a strong surface electric field leads to the best gas-sensitive properties: the sensor’s responsivity is between two and nine times higher than that of sensors based on ZnO-SnO₂ films of other compositions. A study of characteristics sensitive to NO₂ (0.1–50 ppm) showed that gas sensors based on the ZnO-SnO₂ film demonstrated a high sensitivity to NO₂ with a concentration of 0.1 ppm at an operating temperature of 200 °C.

Thin nanocomposite films based on tin dioxide with a low content of zinc oxide (0.5–5[ ]mol.%) were obtained by the sol–gel method. The synthesized films are 300–600[ ]nm thick and contains pore sizes of 19–29[ ]nm. The resulting ZnO–SnO₂ films were comprehensively studied by atomic force and Kelvin probe force microscopy, X-ray diffraction, scanning electron microscopy, and high-resolution X-ray photoelectron spectroscopy spectra. The photoconductivity parameters on exposure to light with a wavelength of 470[ ]nm were also studied. The study of the photosensitivity kinetics of ZnO–SnO₂ films showed that the film with the Zn:Sn ratio equal to 0.5:99.5 has the minimum value of the charge carrier generation time constant. Measurements of the activation energy of the conductivity, potential barrier, and surface potential of ZnO–SnO₂ films showed that these parameters have maxima at ZnO concentrations of 0.5[ ]mol.% and 1[ ]mol.%. Films with 1[ ]mol.% ZnO exhibit high response values when exposed to 5–50[ ]ppm of nitrogen dioxide at operating temperatures of [ ]C and [ ]C.