Room temperature CH4 sensing properties of Au decorated VO2 nanosheets

The properties of semiconductor materials are greatly affected by electrical and chemical processes occurring at their surfaces. Precise control over surface doping metal nanoparticles can affect the surface charge properties in conventional semiconductor materials. Here, we synthesized vanadium dioxide nanosheets by simple chemical vapor transport deposition method (CVD). Gold nanoparticles were decorated on the VO2 nanosheets surface by ion sputtering. The as-synthesized Au decorated nanosheets were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) equipped with an energy dispersive X-ray spectroscopy (EDS). The sensing performance of as-grown product was studied for different concentrations of methane (CH4) (100-500 ppm) at room temperature. The results reveal that Au decorated VO2 nanosheets exhibit good sensor response toward CH4. The increase in response performance was attributed to the hetero-junction generated in the interface of VO2 nanosheets and Au nanoparticles, and the depletion layer generated in the process of adsorption-desorption kinetic in the interface of the VO2 nanosheets and Au nanoparticles.