Ag−Au−Ag Heterometal Nanowires: Synthesis, Diameter Control, and Dual Transversal Modes with Diameter Dependency

Abstract

We report on the synthesis of Ag−Au−Ag heterometal nanowires through an epitaxial seed-mediated growth of silver nanowires from gold decahedral seeds. The diameter of the Ag−Au−Ag nanowires is precisely controlled in a range of 60−150 nm by using gold decahedral seeds with corresponding edge sizes. The three transversally excited bulk, localized, and propagating modes exhibit optical signatures in the UV−vis spectra. In particular, the end-on incidence propagating mode is highly sensitive to the nanowire diameter. Such exact control of diameters and diameter-dependent surface plasmon modes are expected to be useful for photonic circuit elements and chemical and biosensors.