Synthesis and characterization of a large amount of branched Ni2Si nanowires

A large amount of Ni2Si nanowires sheathed with amorphous silicon oxide has been generated from Ni substrates, for the first time, by thermal chemical vapor deposition using SiH4 gas at 500 degreesC. The Ni2Si nanowires obtained possess substantial amounts of branches (about 2mum length) grown on the main stems (about 30-80-nm diameter and 10-20-mum length). High-resolution transmission electron microscopy and electron diffraction have revealed the orthorhombic Ni2Si phase and the orientation. At the tail end along the branch grown on a stem an amorphous phase was also observed. The Raman spectrum was further used to characterize the product. A possible growth process of the branched Ni2Si nanowires is briefly discussed.