Researchers from Finland and Taiwan have discovered how graphene can be made into 3D objects by using laser light. The scientists provided an illustration, in which they fabricated a pyramid with a height of 60 nm (about 200 times larger than the thickness of a graphene sheet).
"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 the team. "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".
The team shares that at first, the experimental data seemed to make no sense; But results from experiments and computer simulations revealed the formation mechanism of the 3D shapes. "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 the team.
The new 3D graphene is reportedly stable and has electronic and optical properties that differ from normal 2D graphene. Optically forged graphene can help in fabricating 3D architectures for graphene-based devices.