Structural investigation of germanium-cobalt core shell nanocable arrays

The compositional structure of high density arrays of coaxial nanocables, consisting of germanium nanowires surrounded by cobalt nanotube sheaths, within anodic aluminium oxide membranes, were investigated by various X-ray analysis techniques. The nanocable arrays were prepared using a supercritical fluid inclusion process, whereby the cobalt nanotube precursor was first deposited on the pore walls of the nanoporous membranes and subsequently filled with germanium to form coaxial nanocables. The composition and structure of both the as-synthesised (450 degrees C) and annealed (850 degrees C) nanostructures were investigated by X-ray diffraction at high angles (XRD), X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge spectroscopy (XANES).