Self-assembled ge nanostructures on polymer-coated silicon: growth and characterization

Abstract

Self-assembled Ge nanoparticles have been grown on polymer-coated Si substrates by thermal evaporation under high vacuum utilizing the nonwetting condition given by the surface free-energy relation σ _Ge»σ_polymer. The nanostructures have been characterized by Raman spectroscopy, atomic-force microscopy (AFM), and optical microscopy. Raman spectrum shows a prominent Ge-Ge vibration peak at 302cm^-1. AFM and optical microscopy show the formation of isolated Ge islands (>~100nm base, <~25nm height), nanowires (160 nm base, 25 nm height), and islands in linear chains. The possibility of embedding such nanostructures in waveguide structures are discussed.