Synthesis and Characterization of CdO–SnO2 Nanocomposite and Perovskite CdSnO3 Thin Films for Gas Sensing Application

In this study, CdO–SnO2 nanocomposite and CdSnO3 perovskite thin films were synthesized using the spray pyrolysis technique at a substrate temperature of 350°C. The composition of cadmium (Cd) and tin (Sn) was varied in the ratios of 25:75, 50:50, and 75:25. The resultant thin films were analysed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDAX), and transmission electron microscopy (TEM). XRD analysis confirmed the formation of both CdO–SnO2 nanocomposite and CdSnO3 perovskite phases. FESEM revealed spherical nanoparticles for CdO–SnO2 and cubic nanoparticles for CdSnO3, while TEM analysis showed particle sizes ranging from 21 to 27 nm. The gas sensing performance of prepared thin films were tested for various gases, including LPG, CO, CO2, and H2, at operating temperatures from room temperature (RT) to 450°C. The film with a 50:50 composition demonstrated the highest gas response to LPG, with a peak response observed at 300°C and 50 ppm LPG concentration. Notably, this thin film exhibited a quick response time of 40 s and a rapid recovery time of 80 s, highlighting its potential for efficient gas sensing applications.