A simple approach for large-area fabrication of Ag nanorings

A simple and low-cost method based on a two-step heat treatment of AgNO(3)/SiO(2) film has been developed for fabricating metal Ag nanoring arrays. The as-prepared nanorings have an inner diameter of 70-250 nm and an average wall thickness (namely wire diameter) of approximately 30 nm with a number density of approximately 10(9) cm(-2) on the surface of the SiO(2) matrix. X-ray diffraction (XRD) results reveal that these nanorings exhibit a face-centered cubic crystal structure. Furthermore, a new growth mechanism, namely a molten metal bubble as a self-template, is tentatively proposed for Ag nanorings.