Atomic scale direct-write dopant patterning on graphene

The properties of many devices and potential technologies depend on the precise position of a few dopant atoms, meaning that one of the requirements for future generations of nanofabrication will be the ability to insert dopants at well-defined locations. The problem is that most fabrication methods do not achieve the atomic scale position resolution that new quantum devices will require.

In parallel, the recent advent of pseudo-2D and monolayer materials has opened a new landscape to explore. For example, twisted bilayer graphene is an atomically thin, tunable material with exotic quantum properties that depend sensitively on the stacking details and twist angle. The ability to insert dopants at specific locations could be an important way to functionalize and exploit such materials.

This talk will examine routes towards atomic-scale direct-write patterning on graphene. The focused electron beam in a scanning transmission electron microscope (STEM) is used to define attachment points for foreign atoms. Sample temperature is used to control the supply of dopant atoms, which can selectively replace carbon atoms in the lattice. Using image-based feedback-control, arbitrary patterns of atoms and atom clusters are attached to the graphene with limited human interaction.