Ethanol sensing with Au-modified ZnO microwires

A room temperature ethanol sensor based on Au-modified zinc oxide microwires (Au/ZnO MWs) is demonstrated. Au nanoparticles (Au NPs) were immobilized via ion sputtering onto the surface of CVD-fabricated ZnO microwires (ZnO MWs) to serve as sensitizers. Au modification was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and photoluminescence. Gas-sensing tests indicated that the modified microwires exhibited an enhanced performance relative to the unmodified ZnO microwires over a wide gas concentration range, with very stable repeatability, fast recovery time and high sensing response and selectivity. A sensing mechanism is described in terms of localized surface plasmon resonance (LSPR) effect of Au NPs. The superior sensing characteristics indicate the device's potential applications as room-temperature gas sensor, and a straightforward and economical fabrication also makes it very attractive for more widespread use.