Formation of a Multi-Arm Branched Nanorod of ZnO on the Si Surface via a Nanoseed-Induced Polytypic Crystal Growth Using the Hydrothermal Method

Abstract

A branched nanorod of ZnO composed of multiple branches that projects from a single nanorod backbone can be realized by using a hydrothermal approach in the presence of a nanoseed with a special structure, namely multi-faceted orthorhombic Zn2SiO4. Orthorhombic Zn2SiO4 was prepared by annealing the ZnO nanoseed of size ca. 15 nnn on a Si substrate at a temperature of 900 degrees C in air for one hour. A typical branched nanorod was constructed by a hexagonal-and rectangular-shaped nanorod arm. HRTEM analysis on the branched structure indicated that the branches exhibited a different crystal growth direction [002] and [100], reflecting the presence of a polytypic growth process in the formation of the branched nanorod structure. The branched nanorod of ZnO and its feature-rich faceted property appears promising for solar cell, catalytic and sensing applications.