Influence of Au Nanoparticle Surface Decoration on Highly Oriented SnO2 Nanorods/ZnO Hybrid Films for Gas Sensing Improved Performance

Hybrid films containing SnO₂ nanorods and ZnO michrorods were grown by a low-temperature vapor-liquid-solid (VLS) technique. Au nanoparticle decoration on the SnO₂ and ZnO structures was succesfully carried out simultaneously by using a UV wavelength light source and a simple bath solution of HAuCl₄·4H₂O in ethanol. Surface morphologies and structural properties of the Au decorated SnO₂ & ZnO structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The Au decorating nanoparticles were found to be 10nm in average size showing an even dispersion along the hybrid films. Average sizes of the SnO₂ nanorods and ZnO michrorods were reported previously elsewhere. Gas sensing measurements for acetone vapor, ethanol vapor, and carbon monoxide were carried out and compared using three different transducer films consisting in pure SnO₂ film, undecorated SnO₂ & ZnO hybrid film, and Au decorated SnO₂ & ZnO hybrid film. Surface area and Au decoration dramatically influence the sensing device performance and this features are discussed in the present work.