B-rich nanowires are grown on Ni coated oxidized Si(111) substrate using diborane as the gas precursor in a CVD process at 20 torr and 900°C. These nanowires have diameters around 20–100 nanometers and lengths up to microns. Icosahedron B12 is shown to be the basic building unit forming the amorphous B-rich nanowires as characterized by EDAX, XRD, XPS, and Raman spectroscopies. The gas chemistry at low [B₂H₆]/ [N₂] ratio is monitored by the in situ mass spectroscopy, which identified N₂ as an inert carrier gas leading to formation of the B-rich compounds. A nucleation controlled growth mechanism is proposed to explain the rugged nanowire growth of boron. The role of the Ni catalyst in the synthesis of the B-rich nanostructures is also discussed.

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