Crystallinity of Silicon-Shells Deposited onto Germanium and Silicon Nanowires for Core-Shell Nanostructures and Nanotubes

Core-shell nanowires are an essential component of numerous nanoscale device concepts. In this study, germanium and silicon nanowires were synthesized bottom-up using the vapor-liquid-solid technique and successively modified with a silicon shell. The shell synthesis was studied with focus to the crystallinity but includes as well the electrical characteristics of n- and p-doped radial core-shell nanowire devices. Furthermore, the influence of certain post-annealing procedures on the crystallinity of the core-shell nanowires are discussed. We demonstrate that the crystallinity of the silicon shell can be tuned from single-crystalline to amorphous in a controlled manner, independent on a p- or n-type doping, by deliberate adjustment of the growth parameters.