Field enhanced fabrication of metallic nanostructures using millisecond-pulsed scanning tunnelling microscopy

Scanning tunnelling microscopy (STM) can be used as an effective tool for the manipulation of atoms on surfaces. However, it is a laborious procedure, often taking several hours to construct even the simplest patterns. To address this constraint, we have investigated the use of distinct tip geometries combined with voltage pulsing in an STM as a method of rapid nanostructure fabrication. A computational finite-element based electrostatic model enables those tip geometries which can lead to a particular geometrical pattern to be identified. The predictions in the case of a truncated circular cone are confirmed by experimental observation using voltage-pulsed STM. Constructs comparable both in size and morphology to quantum corral type structures were constructed with assembly times in the millisecond regime. The mechanism of formation is discussed.