Fabrication of monocrystalline refractory metal nanostructures capable of ballistic electron transport

Abstract

Refractory metal monocrystalline nanostructures with spatial resolution up to 200 nm are fabricated by subtractive electron lithography and Al mask patterning of epitaxial refractory metal films. The size (width) effect on electrical properties of bridge-type metallic nanostructures with residual electron mean-free paths 200-500 nm is observed for the first time. It is also found that the change of the positive sign of electrical bending resistance at room temperature to the negative one at helium temperature proves the realization of the ballistic limit in electron transport in cross-type nanostructures. The effect of both ion etching and thermal annealing of nanostructures is also investigated.