Nanoscale structural engineering via phase segregation: Au-Ge system.

A tunable structural engineering of nanowires based on template-assisted alloying and phase segregation processes is demonstrated. The Au-Ge system, which has a low eutectic temperature and negligible solid solubility (<10(-3) atom %) of Au in Ge at low temperatures, is utilized. Depending on the Au concentration of the initial nanowires, final structures ranging from nearly periodic nanodisk patterns to core/shell and fully alloyed nanowires are produced.