Growth of single-crystalline nickel silicide nanowires with excellent physical properties

Abstract

High quality single-crystalline NiSi₂, Ni₂Si and Ni₃₁Si₁₂ nanowire arrays coated with amorphous silicon dioxide were synthesized in high quantity by a nickel transport chemical vapor deposition (CVD) method. The morphological changes with various reaction temperatures, ambient pressures and reaction times, were observed and studied. At 750 °C and 850 °C, cone-shaped nanowire arrays were formed, composed of dense and oriented Ni₃₁Si₁₂ and Ni₂Si nanowires with lengths of over 60 μm. The growth mechanisms of the nickel silicide nanowires have been proposed and identified with microscopy studies. Field emission measurements show that the as-grown NiSi₂, Ni₂Si and Ni₃₁Si₁₂ nanowires were of remarkable field enhancement factors, 2532, 4822 and 4099, respectively, and magnetic property measurements show ferromagnetic characteristics for the Ni₂Si and Ni₃₁Si₁₂ nanowires, demonstrating promising potential applications for field emitters, magnetic storage, and biological cell separation.