Morphology Control of Hydrothermally Grown ZnO Nanostructures by Additives and Seed Layers

Abstract

We present a rational control over the morphology of hydrothermally grown ZnO nanostructures by introducing different additives, sequential seeding, and multilayer seeds. The aspect ratio of the ZnO nanorods could be tuned with different types of additives (surfactant, amine, metal salt, and polymer additives) at an appropriate concentration in solution for ZnO hydrothermal growth. Some of the metal salts induced change in both aspect ratio and coverage simultaneously. The degree of vertical alignment of the ZnO nanowires was influenced by the number of seed layers. Furthermore, hierarchical ZnO nanostructures could be fabricated for thermal annealing on a secondary seed layer. The various control parameters demonstrated in this study provide beneficial information that can be used to guide a new strategy for relevant future applications.