Template-free fabrication of a highly ordered ZnO hierarchical structured wire array and its application to gas sensing

A highly ordered ZnO hierarchical structured wire array is fabricated by a template-free electrodeposition combined with subsequent annealing, which realizes a novel spatial combination of horizontally equidistant wires and surface approximately perpendicular lamellar structure. The wires show a surprising uniformity in interspacing, width and surface morphology. The deposited morphology from the initial dendritic pattern to parallel wires array is realized by adjusting the applied voltage. The sensors based on the ZnO wires array shows good selectivity, repeatability and low concentration detection limits to HCHO. This study provides a new direction in fabricating highly ordered hierarchical structured wire arrays for gas sensing applications.