Received December 29, 2006

Revised March 1, 2007

Abstract:

Ultralong, single-crystal Ni₂Si nanowires sheathed with amorphous silicon oxide were synthesized on a large scale by a chemical vapor transport (CVT) method, using iodine as the transport reagent and Ni₂Si powder as the source material. Structural characterization using powder X-ray diffraction, electron microscopy, and energy-dispersive spectroscopy shows that the nanowires have Ni₂Si-SiO_x core-shell structure with single-crystal Ni₂Si core and amorphous silicon oxide shell. The oxide shell is electrically insulating and can be removed by HF etching. Four-terminal electrical measurements show that the single-crystal nanowire has extremely low resistivity of 21 ·cm and is capable of supporting remarkably high failure current density >10⁸ A/cm². These unique Ni₂Si nanowires are very attractive nanoscale building blocks for interconnects and fully silicided (FUSI) gate applications in nanoelectronics.

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