Size-dependent electronic structures of ZnO nanowires

摘要

ZnO nanowires with a diameter distribution from 20 to 100 nm were fabricated by a simple thermal evaporation process. Two different types of nanowire (circular versus hexagonal cross section) were obtained by controlling the growth conditions. The size-dependent electronic structures of both types of samples were investigated using valence electron energy-loss spectroscopy. Both the common features (surface plasmon, bulk plasmon width) and the differences (O 2s interband transition, bulk plasmon energy) between the two types of samples are discussed. The experimental results strongly suggest that ZnO nanowires with hexagonal cross section and low-index terminating surfaces are of high electronic quality, even at 20 nm diameter, and can thus serve as effective building blocks for optoelectronic nanodevices.