Role of metal impurities in the growth of chains of crystalline-silicon nanospheres

Abstract We reported a novel silicon nanostructure, a chain of crystalline-silicon nanospheres: crystalline-silicon nanospheres are covered with and connected by silicon oxide at a nearly equal spacing forming a chain-like nanostructure. We have found that additional metal impurities such as lead can promote a periodic instability in the vapor–liquid–solid growth of silicon nanowires resulting in the chain formation. By controlling the metal impurities, we have successfully grown dense chains and also measured their phonon structures. Through the analysis of Raman spectra, we have found that the phonons were confined in the silicon nanospheres.