University of Jyväskylä

Graphene forged to three dimensional shapes

Researchers from the University of Jyväskylä in collaboration with researchers from Taiwan have discovered how graphene, a single atom thin layer of carbon, can be forged into three-dimensional objects by using laser light. A new laser writing technique helps to develop new products containing graphene. The results have been recently published in Nano Letters.

Graphene is a close relative to graphite which consists of millions of layers of graphene and which can be found from a common pencil tip. Graphene can be used to make electronic and optoelectronic devices, such as transistors, photodetectors and sensors. In future, we will probably see an increasing number of products containing graphene.

The new graphene devices in the future

The novel 3D graphene is stable and it has electronic and optical properties that differ from normal 2D graphene. Optically forged graphene opens a way for fabrication of 3D architectures for graphene-based devices. A striking illustration was provided by fabrication of a pyramid having a height of 60 nm, which is about 200 times larger than the thickness of a graphene sheet. The pyramid was so small that it would fit easily on a hair.

 “We call this technique optical forging since the process resembles forging of metals into 3D shapes by a hammer. In our case a laser beam is the hammer which 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 is fast and easy to use, and it does not 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 so substantial changes on graphene. It took a while to understand what is really happening”, he continues.

In the beginning, we were flabbergasted. The experimental data simply made no sense, but gradually, by close interplay between experiments and computer simulations, the actuality of 3D shapes and their formation mechanism started to clear up.”, says Dr. Pekka Koskinen, also from the Nanoscience Center, who was responsible for the theory.

The research was done at the Nanoscience Center (NSC), University of Jyväskylä by Andreas Johansson, Pasi Myllyperkiö, Pekka Koskinen, Jukka Aumanen, Juha Koivistoinen, Vesa-Matti Hiltunen, Jyrki Manninen and Mika Pettersson, at the National Central University of Taiwan by Hung-Chieh Tsai and Wei Yen Woon and at the National Synchrotron Radiation Research Center, Taiwan by Chia-Hao Chen and Lo-Yueh Chang. The research was supported by the Academy of Finland and Ministry of Science and technology of the Republic of China.

Pyramid made from graphene. Similar structure was made experimentally by using laser irradiation in a process named “optical forging”.

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