Researchers create a functional semiconductor made from graphene

Silicon, the semiconductor material used to make most of modern electronics, is reaching its limit as increasingly faster computing and smaller electronic devices are being developed. Now, as an alternative, researchers have created the world’s first functional semiconductor made from graphene, a single sheet of carbon atoms held together by the strongest bonds known.

Researchers from the Georgia Institute of Technology have developed a graphene semiconductor that is compatible with conventional microelectronics processing methods. 

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A constant hurdle in graphene research was the ‘band gap,’ which refers to an important electronic property that allows semiconductors to switch on and off. It’s because of the lack of band gap in graphene that many people have doubted the possibility of graphene electronics, a press statement explained. The main question in graphene electronics research was how to switch it on and off so it can work like silicon.

The researchers achieved a breakthrough when they figured out how to grow graphene on silicon carbide wafers using special furnaces. They produced epitaxial graphene, which is a single layer that grows on a crystal face of the silicon carbide, the statement explained. When this was made properly, the epitaxial graphene chemically bonded to the silicon carbide and started to show semiconducting properties.

“We now have an extremely robust graphene semiconductor with 10 times the mobility of silicon, and which also has unique properties not available in silicon,” lead author Walter de Heer said in the statement. 

However, to make a functional transistor, a semiconducting material must be manipulated significantly, which can damage its properties. To prove that their graphene material could function as a viable semiconductor, the researchers had to measure its electronic properties without damaging it, the statement says.

For this, they put atoms on the graphene that “donate” electrons to the system, which is a technique called doping. This checks whether the material is a good conductor. In this case, it worked without damaging the material or its properties. The findings were published recently in the journal Nature.

De Heer also added that the graphene material is more efficient, it doesn’t heat up as much, and it allows for higher speeds so that the electrons can move faster. Furthermore, the researchers have mentioned that the new material is currently the only two-dimensional semiconductor that has all the necessary properties to be used in nanoelectronics.

In the statement, co-author Lei Ma confirmed that their technology achieves the band gap, and this is an important step in realising graphene-based electronics. The study also highlighted that the new material allows the use of quantum mechanical wave properties of electrons, which is a requirement for quantum computing.