Predictions have been made that graphene will eventually be a substitute for silicon in electronics, but making it in large quantities is a challenge. Scientists have made progress since the days when they used scotch tape to pull off a layer of graphene from graphite, but most contemporary methods aren’t yet robust enough for large-scale manufacturing, especially for the applications that require graphene with varying numbers of layers at random positions.
“You can imagine trying to peel a piece of shrink wrap off a dish to put it on a new dish – it’s going to be messy,” said lead researcher Jiwoong Park, Cornell assistant professor of chemistry and chemical biology.
The Cornell group’s new method is to grow the graphene directly onto silicon wafers coated with a special evaporated copper film. They then cut the graphene films into their desired shapes using such standard methods as photolithography. Finally, they move the underlying copper with a chemical solution. What is left is a graphene film that draped down over the silicon wafer with little defect.
“Once the graphene is made on top of this wafer, you can apply any thin-film processing technique,” Park said.
The team is now experimenting with growing four-inch wafers, which would further demonstrate the manufacturing potential of graphene-based electronics.