NO2 gas sensing properties of ZnO sheathed CuO nanorods

CuO-core/ZnO-shell one-dimensional nanostructures have been fabricated by a two-step process: thermal oxidation of a copper foil and atomic layer deposition of ZnO. The structure and gas sensing properties of the nanostructures have been investigated by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, and PL spectroscopy techniques. The nanostructures were found to have a form of nanorods with the diameters in a range from a few tens to a few hundreds of nanometers and the lengths of a few tens of micrometers. The CuO cores had a crystalline monoclinic structure, whereas the ZnO shells had an amorphous structure. The gas sensors fabricated from multiple networked CuO-core/ZnO-shell nanorods showed somewhat degraded electrical responses to NO2 at 300 degrees C. This degradation may be due to the opposite behaviors of the CuO core and ZnO shell. Copyright (C) 2012 John Wiley & Sons, Ltd.