Researchers at the Massachusetts Institute of Technology (MIT) and University of Michigan have developed a graphene fabrication process that places graphene directly on materials such as large sheets of glass, a process that lends itself to scaling up.
Currently, most methods of making graphene first grow the material on a film of metal, such as nickel or copper. But the process of transferring graphene from metal to substrate has become much more frustrating than the process of growing the graphene itself, and can damage and contaminate the graphene, according to A. John Hart Hart, MIT Mitsui Career Development Associate Professor of Mechanical Engineering.
In the new process, graphene is deposited using chemical vapor deposition (CVD) on both the top and the bottom of the metal film. The nickel film on top of the silicon dioxide substrate can then be peeled away, leaving just the graphene on top of the nonmetallic substrate.
The process eliminates a separate step to attach the graphene to the intended substrate. "You do the CVD on the substrate, and, using our method, the graphene stays behind on the substrate," Hart said.
"We were inspired by the need to develop a scalable manufacturing process that could produce graphene directly on a glass substrate," said Hart. The inspiration to make the process scalable came from collaborating with Guardian Industries, a large glass manufacturer which uses a float process, where glass moves along at a speed of several meters per minute in facilities that produce hundreds of tons of glass every day.
While the work is in an early stage the ability to produce graphene directly on nonmetal substrates could be used for large-format displays and touch screens, and for 'smart' windows that have integrated devices like heaters and sensors, according to the researchers.
They describe the process in detail in the? journal Scientific Reports.
Guardian Industries, the National Science Foundation, and the Air Force Office of Scientific Research supported the research.