Facile Synthesis of Nano-Diced SnO2-ZnO Composite by Chemical Route for Gas Sensor Application

The simple chemical bath deposition (CBD) method is used to synthesize SnO2-ZnO nanocomposite at room temperature. Formation of SnO2-ZnO nancomposite is confirmed by the x-ray diffraction (XRD) pattern of annealed films. Scanning electron microscopy (SEM) micrographs of nanocomposite SnO2-ZnO depict that morphological change from nanocubes to manifold hexagonal nanorods with an increase in ZnO content in a composite sample. Also, pure SnO2 sample exhibits interconnected nanospheres. Electron dispersive spectroscopy (EDS) is employed to confirm elemental compositions in composite films. SnO2-ZnO samples were applied as a sensor for different test gases, namely liquified petroleum gas (LPG), ethanol, ammonia (NH3), and hydrogen sulfide (H2S). The maximum response of 59.67% is observed for ethanol at an operating temperature of 275 degrees C and 24 ppm gas concentration. Also, a composite sensor shows a quick response in comparison with a bare sensor. This superior performance of composite over pure sensor may be attributed to a n-n heterojunction at intergrain boundaries. The SnO2-ZnO sensor is found to be selective towards ethanol even at lower gas concentrations.