Structural and sensing properties of ethanol gas using Pd-doped SnO2 thick film gas sensor.

In the present study, we fabricate undoped and 1 wt% palladium (Pd)-doped tin oxide (SnO2) films were deposited on alumina substrate using screen printing technology. The deposited sensing film is characterized and its microstructural properties are studied using X-ray diffraction (XRD) and atomic force microscope (AFM). The crystallite size, grain size, and roughness parameter decrease with Pd doping. It was ~ 23.5 nm and ~ 19.2 nm for undoped and Pd-doped SnO2 film samples. The response of fabricated thick film sensor for 1 wt% Pd-doped SnO2 is maximum (~ 71) with varying concentrations of ethanol (5000 ppm) at operating temperature 473 K. The response/recovery time is observed and it is ~ 41 s/125 s. The reduction in crystallinity and roughness leads to improves sensing behavior towards ethanol gas. The sensing mechanism and response behavior is explained based on a theoretical model.