The growth and characterization of Si and Ge nanowires grown from reactive metal catalysts

We discuss the benefits of using metals other than Au to catalyze the growth of Si and Ge nanowires, emphasizing the opportunities that these non-conventional materials provide for tailoring electronic and structural nanowire properties. However, since these metals are more reactive than Au, their use creates constraints on wire growth conditions as well as difficulties in post-growth characterization. These issues are illustrated for Si and Si/Ge nanowires grown from Al, Cu and AuAl starting materials. The vacuum requirements for the deposition of the reactive metals are discussed as well as the effect of atmospheric exposure on the structure of wires observed post-growth with electron microscopy.