The preparation of spiral ZnO nanostructures by top-down wet-chemical etching and their related properties

In this paper, we report the synthesis of spiral ZnO nanocrystals by the wet-chemical etching of pyramid ZnO nanoparticles in a solvent mixture of oleic acid (OA) and 1-octylamine. Adequate evidence demonstrates that the OA in the mixed solvent acts as the etching agent. The formation of spiral ZnO nanoparticles is due to dislocations in the spiral shape surrounding the c axis formed during the growth of the pyramid ZnO nanoparticles. Moreover, the spiral ZnO nanoparticles exhibit much better gas sensing activity than the pyramid ZnO nanoparticles. Based on the structural analysis, we discuss the relationship between the surface structures and gas sensing properties.