Hits:

Indexed by:期刊论文

Date of Publication:2011-06-01

Journal:CRYSTAL GROWTH & DESIGN

Included Journals:Scopus、SCIE、EI

Volume:11

Issue:6

Page Number:2135-2141

ISSN No.:1528-7483

Abstract:Using pre-existing ZnO nanowires as lattice-matched templates, we have systematically studied the catalyst-free regrowth of ZnO nanostructures in a chemical vapor deposition (CVD) system. Because the templates (or crystal seeds) provided nanoscale preferential nucleation sites for the subsequent growth, changing ZnO supersaturation and growth temperature led to distinct growth modes, from nonepitaxy to homoepitaxy and from axial to radial epitaxy. The perfect borderless homoepitaxial ZnO nanostructures demonstrate the inherent growth behaviors that were especially researched with the help of their position-dependent optical properties. Neither the self-catalyst vapor-liquid-solid (VLS) growth mechanism nor the defects-induced growth mechanism could explain most of these homoepitaxial growth modes. Instead, two-dimensional nucleation and step propagation model based on avapor-solid (VS) scenario was suggested and all these phenomena were well interpreted. In addition, our work presents a very convenient and well-controlled way of fabricating useful nanostructures in a CVD system.