Fig. 1: Synthesis route and microstructural characterization of the SnO₂-CuO composite film.
a Schematic diagram for the synthesis of the CO2 SAW sensor with SnO2-CuO film. b The digital photo, c SEM image, d EDX mapping energy dispersive spectroscopy, e cross-section SEM image and f AFM image of SnO2-CuO film
