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IBS scientists create a band gap in graphene nanowrinkles

November 9, 2015

Fundamental Element of Life

​​Carbon is found free in nature in three allotropic forms; amorphous, graphite and diamond. Graphite is one of the softest known materials, and diamond is one of the hardest. This difference is purely because of the arrangement of atoms in each of the two forms. In graphite, hexagonal rings are joined together to form sheets that lie on top of one another. Diamond has a slightly more compact structure and its density is greater than that of graphite. The appearance of diamond is well known and, like graphite, it is relatively unreactive but does burn in air at temperatures between 600-800°C. Each carbon atom is bound to four neighbors in a tetrahedron, and so each diamond crystal is a single giant lattice structure.

Manipulation of Carbon
Graphene, a two–dimensional (2-D) material, is a different structural modification of graphite and, as an extension, carbon. It is the thinnest and strongest known material in the universe. Graphene has remarkable attributes; it is stronger than steel yet many times lighter, more conductive than copper and more flexible than rubber. It has been tested and experimented on extensively and, in 2010, earned two scientists the Nobel Prize in Physics for their groundbreaking experiments on the 2-D material. Graphene is thought of as a 2-D material but the reality is not so straightforward. Under certain manipulation graphene can be wrinkled and shaped to resemble a three-dimensional shape, for example a sphere or a tube. The material will also interact with a substrate, further increasing this wonder material’s seemingly boundless properties.
Scientists, from the Center for Multidimensional Carbon Materials within the Institute for Basic Science and RIKEN, have reported the unique electronic structure of graphene nanowrinkles in a graphene sheet grown on Nickel {Ni(111)}, the width of which was small enough to cause one-dimensional (1-D) electron confinement. Graphene wrinkles are a 1-D form of graphene, it is produced by chemical vapor deposition (CVD), a method employed to create high quality, high performance solid materials. In this experiment however the team used a scanning tunneling microscope tip to structurally manipulate the formation of the wrinkles, resulting in band gap openings within the wrinkles, a desirable property effectively making graphene a semiconductor, which had previously only been achievable through chemical modification of graphene.

“Graphene nanowrinkles will be a new wrinkle in graphene electronics. The discovery of semiconducting properties in graphene nanowrinkles implies an imaginary dimension by which the structural shape can also influence the electronic properties in the material,” said IBS researcher Hyunseob Lim, “I believe that the implementation of this new concept will result in great opportunities to develop materials with unique physical and electronic properties.” If metallic-semiconducting-metallic junctions are realized on one graphene sheet in a controlled manner, it has the potential to be used for high performance graphene field effect transistors.

 Figure 1 Scanning Tunneling Microscope tip manipulating graphene nanowrinkles on a graphene sheet

The paper entitled Structurally Driven One-Dimensional Electron Confinement in sub-5-nm Graphene Nanowrinkles was originally published on Nature Communication on October 23.

By Neil Mannix

Notes for editors

- References
Hyunseob Lim, Jaehoon Jung, Rodney S. Ruoff & Yousoo Kim (2015), Structurally Driven One-Dimensional Electron Confinement in sub-5-nm Graphene Nanowrinkles, Nature Communication, DOI: 10.1038/ncomms9601

- Media Contact
Mr. Shi Bo Shim, Head of Department of Communications, Institute for Basic Science (+82-42-878-8189; sibo@ibs.re.kr) or Ms. Sunny Kim, Department of Communications, Institute for Basic Science (+82-42-878-8135; Sunnykim@ibs.re.kr)

- About the Institute for Basic Science (IBS)
IBS was founded in 2011 by the government of the Republic of Korea with the sole purpose of driving forward the development of basic science in Korea It comprises a total of 50 research centers in all fields of basic science, including mathematics, physics, chemistry, life science, earth science and interdisciplinary science. IBS has launched 25 research centers as of October 2015.There are eight physics, one mathematics, six chemistry, eight life science, and two interdisciplinary research centers.