Ion beam processing of Au nanowires.

In nanoelectronics a nanowire forms an elemental building block enabling a charge transfer in complex nanostructures. Ion beam etching has been applied for downsizing of prefabricated Au nanowires in the sub-50 nm linewidth regime, aiming at achieving effective cross sections of less than 10 nm. Low energy Ar+ and Ga+ ions were employed for dry ion beam etching of Au nanowires. Nanometer-precise gradual downsizing to an effective diameter as small as 9 nm has been achieved when using Ar+ ions. In contrast, the chemical nature of Ga and its surface condensation into a nanosized phase turned out to act destructively on the nanowires' morphology, hampering the process of downsizing. In the surface nanocondensate Ga was found to coexist in both solid and liquid states, exhibiting polymorphism and peculiar dynamics under ion irradiation.