Figure 6.

Evolution of the <110>-oriented Ge NW morphology. The NWs initially show (a) an irregular hexagonal cross-section, then (b) a reduction of the gold seed particle and a lateral overgrowth on the {111} sidewall that is exposed to the Ge flux, and finally (c) the disappearance of both the gold seed particle and the {100} sidewalls, giving rise to Ge NW with a rhombohedral cross-section.