Brush-Like Hierarchical ZnO Nanostructures: Synthesis, Photoluminescence and Gas Sensor Properties

Brush-like hierarchical ZnO nanostructures assembled from initial ID ZnO nanostructures were prepared from sequential nucleation and growth following a hydrothermal process. The morphology, structure, and optical property of hierarchical ZnO nanostructures were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) studies. The FE-SEM images showed that the brush-like hierarchical ZnO nanostructures are composed of 6-fold nanorod-arrays grown on the side surface of core nanowires. Compared with ZnO nanowires, brush-like hierarchical ZnO nanostructures easily fabricated satisfactory ethanol sensors. The main advantages of these sensors are featured in excellent selectivity, fast response (less than 10 s), high response (sensitivity), and low detection limit (with detectable ethanol concentration in ppm).