Synopsis: Graphene Doesn’t Mind a Pair of Defects

Scanning tunneling microscopy and spectroscopy experiments show how missing carbon atoms affect graphene’s electronic and magnetic properties.
Synopsis figure
M. M. Ugeda et al., Phys. Rev. B (2012)

With its one-atom-thick, stable lattice structure and high electronic mobility, graphene is anticipated as a possible replacement material for silicon in conventional semiconductor electronics. Tinkering with graphene’s pristine surface, either by introducing foreign molecules or creating defects, is a promising way to control graphene’s properties and functionality. For example, defects can be introduced by knocking out carbon atoms with ion irradiation.

Now, writing in a Rapid Communication in Physical Review B, Miguel M. Ugeda at the Autonomous University of Madrid, Spain, and collaborators report the impact of a common type of defect—a double vacancy, where two neighboring carbon atoms are missing—on graphene’s electronic structure and properties. Based on scanning tunneling microscopy and spectroscopy experiments, as well as ab initio calculations, they infer that the structure surrounding double vacancies is a planar structure with no dangling bonds, and is thus less chemically active than other types of vacancy defects.

On the other hand, the presence of double vacancies does, according to the authors, strongly modify graphene’s electronic structure, creating new electronic states. As a consequence, double vacancies are expected to limit the electron mobility of graphene by acting as traps for charge carriers around the defects. Ugeda et al.’s calculations also show that double vacancies aren’t magnetic like single vacancies, so they do not contribute to the magnetism that has been observed in irradiated graphene systems. – Hari Dahal


Features

More Features »

Subject Areas

NanophysicsGraphene

Previous Synopsis

Next Synopsis

Nonlinear Dynamics

Greed is Good

Read More »

Related Articles

Synopsis: Thermal Radiation Gets a Boost
Nanophysics

Synopsis: Thermal Radiation Gets a Boost

The thermal radiation transfer between two quartz plates separated by a 200-nm gap is 45 times greater than predicted by conventional laws for blackbodies. Read More »

Synopsis: Stretching Graphene Localizes its Electrons
Graphene

Synopsis: Stretching Graphene Localizes its Electrons

The electrical properties of a graphene bilayer can be tuned by stretching and rotating one of the bilayer’s sheets. Read More »

Focus: Taking Temperature in 2D
Graphene

Focus: Taking Temperature in 2D

Electron microscopy can produce nanometer-scale maps of the thermal expansion of 2D materials, which may be important for the development of nanoelectronic devices. Read More »

More Articles