Invited Paper EM+NC-ThM5
Barrier Formation and Transport in Metal Contacts to Nanotubes and Nanowires

Thursday, October 23, 2008, 9:20 am, Room 210

The technology of metal-semiconductor contacts has progressed tremendously over the past fifty years. However, as device dimensions shrink well below 100 nm, and as new materials with novel composition and geometry are explored for 'next generation' electronic components, the underlying physics of metal-semiconductor contacts departs substantially from the early models of Schottky, Mott, and Bardeen. Single wall carbon nanotubes, for example, have a quasi-one-dimensional density of states and a relatively inert surface which results in less Fermi level pinning and a strong dependence of the contact barrier height on the metal workfunction. Nevertheless, the simple Schottky model fails to correctly predict the barrier height dependence on the nanotube band gap. The Schottky model is also inadequate for describing metal-nanowire contacts, even in the absence of strong one dimensional character in the band structure. In my talk, I will review recent experimental results for metal contacts to nanotubes and nanowires, and discuss how the dimensions and geometry of these nanostructures affect barrier formation. I will also discuss situations where bulk-limited transport in nanowires leads to non-linear current-voltage characteristics, and which is often, incorrectly, ascribed to contact effects.