Enhanced tunneling across nanometer-scale metal-semiconductor interfaces

Abstract

We have measured electrical transport across epitaxial, nanometer-sized metal-semiconductor interfaces by contacting CoSi2-islands grown on Si(111) with an STM-tip. The conductance per unit area was found to increase with decreasing diode area. Indeed, the zero-bias conductance was found to be about 10^4 times larger than expected from downscaling a conventional diode. These observations are explained by a model, which predicts a narrower barrier for small diodes and therefore a greatly increased contribution of tunneling to the electrical transport.Comment: 3 pages, 2 EPS-figures; accepted for publication in Appl. Phys. Let