Ultrasensitive and low detection limit of acetone gas sensor based on ZnO/SnO₂ thick films

In this study, we synthesized ZnO/SnO₂ hybrid sensing nanostructures by a sol-gel method. The structures, composition and morphologies of the synthesized products were thoroughly studied by X-ray diffraction (XRD), field-emission electron scanning microscopy (FESEM) and transmission electron microscopy (TEM). After the gas sensing test, we found that the sensing performance of the ZnO/SnO₂ composite is improved obviously compared with that of single components ZnO and SnO₂. The response to 0.5 ppm acetone reaches 3.36, almost twice that of pure ZnO and SnO₂. Meanwhile, the detection limit can be reduced to the ppb level. The enhanced acetone sensing performance was mainly attributed to the formation of n-n heterojunctions and the synergistic effect of ZnO and SnO₂.