Canadian Light Source spots speed bumps in graphene’s electron highway

Saskatoon, SK -Using the Canadian Light Source, a research team led by scientists from the University at Buffalo have produced images of graphene showing how folds and ripples in the nanomaterial act as speed bumps for electrons, affecting its conductivity. The findings, published June 28 in Nature Communications, has implications for the use of graphene in a variety of future products ranging from ultrafast electronics to flexible solar panels and computer touch screens.

Graphene, which is a single-layer of carbon atoms arranged in a honey-comb pattern, is the thinnest and strongest material known.

According to University at Buffalo chemist Dr Sarbajit Banerjee, graphene’s unique structure makes it incredibly conductive, allowing electric charges to speed through it while encountering little resistance – provided the material is completely flat.  However, the images that Dr Banerjee and colleagues captured using the Canadian Light Source’s x-ray spectromicroscopy beamline revealed that folds and kinks in the material warp the cloud of electrons that cover graphene’s surface, making it more difficult for an electric charge to pass along the material.

“When graphene is flat, things just kind of coast along the cloud. They don’t have to hop across anything. It’s like a superhighway,” said Dr Banerjee, an assistant professor of chemistry. “But if you bend it, now there are some obstacles; imagine the difference between a freshly paved highway and one with construction work along the length forcing lane changes. When we imaged the electron cloud, you can imagine this big fluffy pillow, and we saw that the pillow is bent here and there.”

The research team included Dr Banerjee and students from the University at Buffalo, along with scientists with the US National Institute of Standards and Technology, Lawrence Berkeley National Laboratory’s Molecular Foundry, and SEMATECH, a global consortium of semiconductor manufacturers. Other synchrotron data were taken at the National Synchrotron Light Source, Brookhaven National Laboratory.