Seed-catalyzed heteroepitaxial growth and nonlinear optical properties of zinc selenide nanowires

Abstract

Seed-catalyzed, heteroepitaxial growth of high aspect-ratio, uniform ZnSe nanowires is reported, in which Ag₂Se nanoparticles serve as heterogeneous seeds and as epitaxial substrates. Due to the difference in solubility product constants (K_sp: Ag₂Se ≪ ZnSe), Ag₂Se is precipitated before ZnSe and in situ seeds and catalyzes the nanowire growth in a one-pot solution synthesis. The lattice match between metastable tetragonal Ag₂Se{212} and cubic ZnSe{220} planes facilitates the heteroepitaxial growth of ZnSe nanowires. Conversion of small, uniform Ag particles, which are produced from the reduction of Ag⁺ ions by reductants/surfactants such as polyvinyl pyrrolidone (PVP) and oleylamine (OA), into Ag₂Se with small size and high uniformity is shown to be an effective strategy to control the diameter size and distribution of ZnSe nanowires. The third-order nonlinear optical behavior of the as-prepared nanowires has been evaluated by Z-scan measurements.