Electronic and structural analysis of ultra-small-diameter metal disilicide nanowires

Abstract

This work describes an ab initio study of the electronic structure, electron transport, and energetic properties of cobalt disilicide (CoSi2) and nickel disilicide (NiSi2) nanowires with widths ranging from approximately 0.5 to 2.5 nm using density functional theory. The effects of oxidation on the nanowire surface are considered and are found to reduce the ballistic conductance by approximately 27% for both species considered. The cohesive energies for both the bulk species as well as the nanowires are found to be significantly stronger than for copper, indicating excellent structural stability. While the lower limit of electrical resistance calculated via the ballistic conductance is still significantly larger than that of Cu nanowires of comparable dimensions, the strong intrinsic lattice energy of the disilicide nanowires suggests that they can be fabricated without the need for diffusion barriers and will exhibit superior resistance to self-diffusion and electromigration.