Coulomb blockade at 77 K in nanoscale metallic islands in a lateral nanostructure

Clear Coulomb blockade effects have been observed in lateral metal nanostructures fabricated by combined electron beam lithography and ionized beam deposition. Islands between 2 and 3 nm in diameter were formed in a 25 nm gap for which the effective tunneling capacitance is calculated to be 0.2 aF. Clear Coulomb gaps and staircases were observed at 77 K in current–voltage characteristics. The staircases can still be seen at room temperature but the gaps tend to a nonlinearity in I–V characteristics around zero bias voltage. The total device area is about 0.01 μm2.