Periodic chains of gold nanoparticles and the role of oxygen during the growth of silicon nanowires

The introduction of oxygen during the SiO-VLS growth of silicon nanowires causes a shift in SiOx stoichiometry resulting in an increased formation of SiO2 at the nanowire surface. This leads to instabilities of the usual cylindrical nanowire core-shell structure, where the liquid Au/Si alloy droplet at the nanowire tip is incorporated inside a SiO2 nanowire in form of a periodic array of nanoparticles. The structure and the composition of the resulting nanostructure are investigated in detail using high-resolution and analytical transmission electron microscopy. The influence of the oxygen is investigated experimentally and supports our model of the formation mechanism.