FABRICATION OF MONOCRYSTALLINE REFRACTORY-METAL NANOSTRUCTURES CAPABLE OF BALLISTIC ELECTRON-TRANSPORT

Refractory metal monocrystalline nanostructures with spatial resolutio n up to 200 nm are fabricated by subtractive electron lithography and Al mask patterning of epitaxial refractory metal films. The size (widt h) effect on electrical properties of bridge-type metallic nanostructu res 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 o ne at helium temperature proves the realization of the ballistic limit in electron transport in cross-type nanostructures. The effect of bot h ion etching and thermal annealing of nanostructures is also investig ated.