Reductive Self-Assembling of Ag Nanoparticles on Germanium Nanowires and Their Application in Ultrasensitive Surface-Enhanced Raman Spectroscopy

Silver nanoparticles (AgNPs) have been reductively fabricated on the hydrogen-terminated surface of germanium nanowires (GeNWs), which exhibited moderate reactivity toward the direct reduction of Ag (I) ion to metal nanoparticles in aqueous solution at room temperature. The electronic properties of the AgNPs/GeNWs system have been studied by X-ray photoelectron spectroscopy. The Ag nanoparticle-embedded germanium nanowires have been used as a unique surface-enhanced Raman scattering substrate, which could achieve the single molecule detection. The observed enhancement factor of the fabricated AgNPs/GeNWs substrate was estimated to be 10(7).