tailieunhanh - Báo cáo hóa học: " Homoepitaxial regrowth habits of ZnO nanowire arrays"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Homoepitaxial regrowth habits of ZnO nanowire arrays | Liu et al. Nanoscale Research Letters 2011 6 619 http content 6 1 619 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Homoepitaxial regrowth habits of ZnO nanowire arrays Jian Liu Shufan Xie Yanglong Chen Xianying Wang Hongbin Cheng Fang Liu and Junhe Yang Abstract Synthetic regrowth of ZnO nanowires NWs under a similar chemical vapor transport and condensation CVTC process can produce abundant ZnO nanostructures which are not possible by a single CVTC step. In this work we report three different regrowth modes of ZnO NWs axial growth radial growth and both directions. The different growth modes seem to be determined by the properties of initial ZnO NW templates. By varying the growth parameters in the first-step CVTC process ZnO nanostructures . nanoantenna with drastically different morphologies can be obtained with distinct photoluminescence properties. The results have implications in guiding the rational synthesis of various ZnO NW heterostructures. Keywords ZnO nanoantenna photoluminescence second growth Introduction One-dimensional ZnO nanowires NWs have attracted increasing interests for their potential applications in various functional devices including solar cells 1 2 nanosensors 3 nanogenerators 4 and nano-optoelectronics 5 . Compared with other semiconductor NWs ZnO has a large band gap eV and high exciton binding energies 60 meV and thus can be used as ultraviolet laser or lightemitting diodes. In addition ZnO nanostructures also exhibit the richest morphologies reported so far . nanocomb nanoring nanobridge nanonail nanobelt 2 6-9 making it coveted as building blocks for functional devices. Nonetheless the growth of ZnO NWs is sensitive to the fabrication conditions and is often difficult to control . slight changes of the growing parameters may result in drastic differences in morphologies and subsequent semiconducting or optical properties 10 . Although tremendous efforts have been