Fabrication of Nb-doped ZnO nanowall structure by RF magnetron sputter for enhanced gas-sensing properties

摘要

An Nb-doped ZnO nanowall is fabricated by radio-frequency (RF) magnetron sputtering at 250 degrees C for application in a gas sensor. The fabricated Nb-doped ZnO nanowall is characterized by field emission scanning microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The Nb-doped ZnO nanowall is observed to show a predominant exposed polarized (002) plane. The specific surface area is increased relative to that of the parent ZnO nanowall from 9.2 +/- 0.42 m(2) g(-1) to 9.8 +/- 0.52 m(2) g(-1). The segregation of Nb does not occur in the Nb-doped sample observed by TEM; this indicates that the addition of Nb occurs within the solid-solution limit of the ZnO host lattice. The Nb-doped ZnO nanowall gas sensor presents excellent gas sensing properties for acetone and ethanol gases at a relatively low operating temperature. We confirm the effects of Nb-doping on the ZnO nanowall, such as the exposed (002) plane, specific surface area increase, and electronic structural changes. Nb doping of the ZnO host lattice is a promising method that enhances the acetone and ethanol gas-sensing capacity at a relatively low operating temperature. (C) 2016 Elsevier B.V. All rights reserved.