Growth of boron-rich nanowires by Chemical Vapor Deposition (CVD)

Abstract

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 900C ° . These nanowires have diameters around 20-100 nanometers and lengths up to microns. Icosahedron B 12 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 [ B2 H6 ]/ [ N 2 ] ratio is monitored by the in situ mass spectroscopy, which identified N 2 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.