discovered an oxygen-free chemical vapor deposition (OF-CVD) technique. The technique can produce high-quality graphene samples on a large scale, which establishes a direct correlation between oxygen and graphene quality and shows how trace oxygen impacts the growth rate of graphene.
The Hone lab at Columbia Engineering created over 100 identical graphene samples with their oxygen-free chemical vapor deposition method.
Graphene, a single layer of carbon atoms, has been hailed as “the wonder material of the 21st century.” Since its discovery in 2004, it has been hailed for several exceptional qualities, including exceptionally high electrical conductivity and remarkable tensile strength. Graphene could revolutionize electronics, energy storage, sensors, biomedical devices, and other industries.
We show that eliminating virtually all oxygen from the growth process is the key to achieving reproducible, high-quality CVD graphene synthesis. This is a milestone towards large-scale production of graphene.
Scotch-Tape Method:
Uses household tape to peel individual graphene layers from graphite.
Produces very pure graphene samples, free from contaminants.
Samples are small (a few tens of micrometers), suitable for lab research but not for industrial applications.
CVD Growth Method:
Developed about 15 years ago for large-area graphene synthesis.
Involves passing a carbon-containing gas (e.g., methane) over a copper surface at high temperatures.
The carbon atoms reorganize into a graphene layer resembling a honeycomb structure.
Scalable to produce samples from centimeters to meters in size.
Faces challenges with reproducibility and variable quality due to oxygen contamination.
Oxygen Contamination Issue:
Richard Martel and Pierre Levesque demonstrated that small amounts of oxygen can hinder graphene growth and remove it.
Christopher DiMarco designed a CVD system to control oxygen levels during deposition about six years ago.
Improvements by Ph.D. Candidates:
Ph.D. candidates Xingzhou Yan and Jacob Amontree improved the growth system.
Found that removing trace oxygen from the process made CVD growth faster and more consistent.
Developed a model to predict growth rates over various parameters like temperature and gas pressure.
Quality of OF-CVD Graphene:
Oxygen-Free CVD (OF-CVD) produced graphene of almost the same quality as exfoliated graphene.
Demonstrated compelling evidence for the fractional quantum Hall effect in magnetic fields, a quantum phenomenon previously observed in high-quality, two-dimensional systems.
Future Challenge:
The team aims to develop a clean method to transfer high-quality graphene from the metal growth catalyst to functional substrates such as silicon.