Graphene Pyramid Takes 2-D Material into 3-D

“We call this technique optical forging, since the process resembles forging metals into 3D shapes with a hammer. In our case, a laser beam is the hammer that forges graphene into 3D shapes,” explains Professor Mika Pettersson, who led the experimental team at the Nanoscience Center of the University of Jyväskylä, Finland. “The beauty of the technique is that it’s fast and easy to use; it doesn’t require any additional chemicals or processing. Despite the simplicity of the technique, we were very surprised initially when we observed that the laser beam induced such substantial changes on graphene. It took a while to understand what was happening.”

“At first, we were flabbergasted. The experimental data simply made no sense,” says Dr Pekka Koskinen, who was responsible for the theory. “But gradually, by close interplay between experiments and computer simulations, the actuality of 3D shapes and their formation mechanism started to become clear.”

“When we first examined the irradiated graphene, we were expecting to find traces of chemical species incorporated into the graphene, but we couldn’t find any. After some more careful inspections, we concluded that it must be purely structural defects, rather than chemical doping, that are responsible for such dramatic changes on graphene,” explains Associate Professor Wei Yen Woon from Taiwan, who led the experimental group that carried out X-ray photoelectron spectroscopy at the synchrotron facility.

The novel 3D graphene is stable and it has electronic and optical properties that differ from normal 2D graphene. Optically forged graphene can help in fabricating 3D architectures for graphene-based devices.

The research was carried out at the Nanoscience Center (NSC) of the University of Jyväskylä, the National Central University of Taiwan and the National Synchrotron Radiation Research Center in Taiwan.

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