Jan 15, 2024 13:00:00

Researchers succeeded in creating the first functional semiconductor from the popular material 'graphene'

Graphene is a sheet with a honeycomb structure in which carbon atoms are bonded in hexagonal shapes, and while it is hundreds of times stronger than iron, it is extremely lightweight, soft, and has high thermal and electrical conductivity. A research team from the United States and China succeeded in creating the world's first functional semiconductor using such graphene.

Ultrahigh-mobility semiconducting epitaxial graphene on silicon carbide | Nature
https://www.nature.com/articles/s41586-023-06811-0

Researchers Create First Functional Semiconductor Made From Graphene | Research
https://research.gatech.edu/feature/researchers-create-first-functional-semiconductor-made-graphene

First working graphene semiconductor could lead to faster computers | New Scientist
https://www.newscientist.com/article/2410612-first-working-graphene-semiconductor-could-lead-to-faster-computers/

Research in Graphene Shows New Potential for Its Use in Chips - WSJ
https://www.wsj.com/articles/research-in-graphene-shows-new-potential-for-its-use-in-chips-5b2794a4

First ever graphene semiconductor could speed up computers - YouTube


Almost all electronic devices essential to modern society are equipped with semiconductors, and the material used is silicon . However, with the demand for faster calculation speeds and smaller electronic devices, it is said that silicon semiconductors have reached their physical functional limits, and researchers are pursuing semiconductor materials that can replace silicon. I've been doing it.

One candidate for a semiconductor material to replace silicon is graphene, a sheet of carbon atoms. However, semiconductors have a ' band gap ', which is the difference in energy level between the valence band where electrons remain within the crystal and the energy level of the conductor where electrons can move outside, and this electronic property effectively turns the current on and off. However, graphene did not have a band gap.

Previous research has shown that although it has been possible to make graphene function like a semiconductor on a small scale, it has not been possible to scale it up to a size that can be used as a practical computer chip.

Walter de Geer , a physics professor at the Georgia Institute of Technology, has been researching graphene as a potential semiconductor for more than 20 years. 'We were driven by the desire to bring three special properties of graphene into electronics: it is a very strong material and can handle very large currents,' de Geer said. 'And it doesn't overheat or fall apart.'

A research team led by Mr. de Geer succeeded in heating a wafer of

silicon carbide , a compound of carbon and silicon, to evaporate the silicon before the carbon and create a layer of graphene on the wafer. Furthermore, we demonstrated that this graphene layer chemically bonds to silicon carbide and exhibits semiconducting properties.

The research team's measurements showed that graphene semiconductors have 10 times the electron mobility of silicon. This means that electrons move with very low resistance, potentially enabling faster computing in electronic devices. 'It's like driving on a highway versus driving on a gravel road. It's more efficient, it doesn't produce as much heat, and the electrons can move faster,' De Geer said. Masu.

Professor Ma Lei from the Tianjin National Research Center for Nanoparticles and Nanosystems (TICNN) , who co-authored the paper, said: ``A long-standing problem in graphene electronics is that graphene doesn't have the right bandgap and can be turned on and off at the right ratio.'' Over the years, many people have tried to address this problem in different ways. This is an important step.'

Professor David Carey of the University of Surrey in the UK, who was not involved in the research, points out that the use of wafers, which are familiar to the semiconductor industry, to create graphene semiconductors has advantages in scaling up the process. doing. However, many improvements are still needed in terms of transistor size, quality, and manufacturing technology, and he predicted that it will take time to switch from silicon, which is already in practical use, to graphene chips.