High density germanium nanowire growth directly from copper foil by self-induced solid seeding

Herein, we describe the growth of highly dense germanium nanowire mats directly on copper foil by a self-induced, solid seeded protocol. The existence of Cu₃Ge tips on each of the nanowires indicates that growth proceeds via a solid catalyzed route, dependent on the in situ formation of the germanide intermediate. The nanowires show a tight diameter distribution and typically 〈110〉 growth directions resulting from similarities in the d spacings between the nanowire and the catalyst seed. The nanowires and substrates were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), and electron backscatter diffraction (EBSD).