Scanning Tunneling Microscopy of dopants and defect structures in monolayer graphene

The ability of the Scanning Tunneling Microscope (STM) to study material surfaces with atomic resolution makes it a perfect tool for measuring local structural and electronic properties and their relationships. Here we report on an investigation of dopant and defect structures in monolayer graphene. Substitutional doping with boron and nitrogen adatoms, achieved by both gaseous and novel liquid precursor based growth methods, as well as He-ion plasma etching of epitaxially grown graphene on SiC, both produce a wide variety of defect structures with interesting topographic and spectroscopic features. Understanding the nature of these structures in graphene not only provides insight into the growth and structural dynamics of two-dimensional systems, and in particular into the nucleated growth of other 2D materials on defective graphene substrates, but also paves the way for tuning of electronic band-gap, conductivity, local spin and magnetic properties, enabling the development of chemical detectors and other advanced electronic devices.