Au-induced encapsulation of Ge nanowires in protective C shells

In situ annealing experiments (in the temperature range between room temperature and 400 degrees C) in a transmission electron microscope show that Ge nanowires can be encapsulated in graphitic C shells in the presence of C (see figure) if the wire surface is decorated with small amounts of Au. The C shells are demonstrated to provide a protective barrier against nanowire oxidation even after prolonged exposure to ambient conditions.