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Thursday, 08 April 2021

New control mechanism in graphene for electronics applications demonstrated

A new research published in Science Advances demonstrates the possibility to tune graphene terahertz nonlinearity by using a small voltage. ICN2 Group Leader Dr Klaas-Jan Tielrooij participated in this study.

Made of carbon atoms arranged in a hexagonal lattice, graphene is a material just one atom thick. Its peculiar structure gives graphene unique properties, such as a very high electrical conductivity. Arguably, one of the most relevant characteristics of this material for applications in high-frequency electronics is its terahertz (THz) nonlinearity, which allows graphene to alter the frequency components of electric currents that pass through it. Indeed, graphene is by far the most nonlinear electronic material that we know.

A new study, recently published in Science Advances, demonstrated that graphene’s THz nonlinearity can be controlled by applying relatively small electrical voltages. To find this, researchers fabricated a device resembling a transistor, where it was possible to control the gate voltage applied to the graphene. Ultrahigh-frequency THz signals were transmitted using the device: the transmission and subsequent transformation of these signals were then analysed as a function of the voltage applied.

The researchers found that graphene’s nonlinear response almost disappears at a certain voltage. This nonlinearity can be efficiently tuned by increasing or lowering the voltage applied. The remarkable results of this research pave the way for exploiting graphene in applications that require a straightforward control of its nonlinear behaviour, for example for the switching and processing of high-frequency electrical signals.

The study was led by Prof. Dr Dmitry Turchinovich, from Bielefeld University (Germany). ICN2 group leader Dr Klaas-Jan Tielrooij and other members of the ICN2 Ultrafast Dynamics in Nanoscale Systems group participated in this work.

 

 

Information via:

https://www.uni-bielefeld.de/ 

 

Press release:

Graphene: Everything under control | EurekAlert! Science News

 

Reference article:

Sergey Kovalev, Hassan A. Hafez, Klaas-Jan Tielrooij, Jan-Christoph Deinert, Igor Ilyakov, Nilesh Awari, David Alcaraz, Karuppasamy Soundarapandian, David Saleta, Semyon Germanskiy, Min Chen, Moham-med Bawatna, Bertram Green, Frank H. L. Koppens, Martin Mittendorff, Mischa Bonn, Michael Gensch, and Dmitry Turchinovich: Electrical tunability of terahertz nonlinearity in graphene. Science Advances, Vol. 7, no 5, April 2021. DOI: 10.1126/sciadv.abf9809