Graphene Manipulation on 4H-SiC(0001) Using Scanning Tunneling Microscopy

TL;DR

This study used advanced STM techniques to manipulate and analyze the atomic-scale topography of multilayer graphene on 4H-SiC(0001), revealing new nano-ridge structures and the effects of electrostatic forces.

Contribution

It demonstrates the use of electrostatic-manipulation STM to systematically alter graphene morphology at the nanoscale, providing insights into force and energy requirements for such modifications.

Findings

Observed nano-ridges ten times smaller than previous records

Demonstrated reversible and permanent graphene morphology changes

Calculated electrostatic forces and energies involved in manipulation

Abstract

Atomic-scale topography of epitaxial multilayer graphene grown on 4H-SiC(0001) was investigated using scanning tunneling microscopy (STM). Bunched nano-ridges ten times smaller than previously recorded were observed throughout the surface, the morphology of which was systematically altered using a relatively new technique called electrostatic-manipulation scanning tunneling microscopy. Transformed graphene formations sometimes spontaneously returned to their original morphology, while others permanently changed. Using an electrostatic model, we calculate that a force up to ~5 nN was exerted by the STM tip, and an energy of around 10 eV was required to alter the geometry of a ~100 X 200 nm^2 area.