Better than Graphene
A Korean research team has succeeded in developing a technology to make a new 2D structure that is superior to graphene in electrical characteristics, which could be used in not only semiconductor devices, but also the fields of energy storage, organocatalysis, and biology.
A research team led by Baek Jong-beom, professor at the School of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology, announced on March 8 that they have successfully developed a technique to synthesize a new 2D structure (C2N-h2D crystal) by utilizing two different benzene compounds where six carbon atoms are combined in a hexagonal shape. The new 2D structure is composed six benzene rings connected with nitrogen atoms in a larger hexagonal shape.
Professor Baek explained that this structure proved to be 100 times better than existing silicon semiconductors in the on/off ratio, after analyzing its structure and evaluating its performance.
The on/off ratio refers to a ratio of current in semiconductors. An increase in the ratio helps effectively control the amount of current in semiconductors, which makes it possible to make high-performance semiconductors.
There is a certain limit in improving the performance of the silicon used in semiconductors, as the production process becomes minute. As a result, many studies have been conducted to develop materials to replace silicon. In particular, graphene is receiving a lot of attention as a next-generation material owing to its excellent properties.
However, graphene is a conductor without a band gap, an energy range in a solid where no electron states can exist. The material is difficult to be used as a semiconductor, since it is impossible to control the electric current.
The band gap is necessary to control the electric characteristics of materials. To use graphene as a semiconductor, its structure has to be changed in a way that controls the flow of the electric charge. It can be done by widening the gap using a chemical method.
The newly-developed structure has a hexagonal shape consisting of six benzene rings with a combination of carbon and nitrogen to scale. After it was examined using a scanning tunneling microscope, it was found that there was a band gap between the graphene and its inside.
Furthermore, the structure's on/off ratio is 100 times better than that of silicon semiconductors.
The study was funded by Korea’s Ministry of Science, ICT and Future Planning, under the Project to Nurture Leading Creative Researching Experts Program. The research findings were first published online on March 6 by Nature Communications, a bi-monthly scientific journal published by the Nature Publishing Group.