Flat crystal with integrated electrode

Researchers pave the way for electronic circuits composed of graphene

Graphene is one of the most promising new materials due to its physical and chemical properties. Researchers from the Friedrich-Alexander University of Erlangen-Nuremberg (FAU) have now developed a procedure which can systematically control graphene components using an integrated electrode – an important prerequisite for industrial applications. Prof. Dr. Heiko Weber, Daniel Waldmann, Johannes Jobst, Dr. Michael Krieger from the Department of Applied Physics and Prof. Dr. Thomas Seyller und Florian Speck from the Department of Technical Physics, have now had their research findings published in the well-known journal “nature materials” (DOI: 10.1038/NMAT2988).

Graphene (emphasis on the last syllable) is composed of a monolayer of carbon atoms, arranged in a hexagonally composite network. The nature of the arrangement makes graphene the first true two dimensional all-solid. Thus, graphene has established a new class of materials. Its discovery in 2004 led to research activities worldwide not seen since the discovery of the high-temperature superconductor. In 2010 the discovery of graphene was awarded the Nobel Prize for Physics. Enthusiasm amongst researchers for this new material has been fed by graphene’s electronic, optical and magnetic properties, which are completely new for a solid. These revolutionary properties present researchers with captivating new dimensions to be explored in physics and at the same time also offer unforeseen potential for applications ranging from innovative semiconductor devices to chemical and biological sensors and quantum computers.

In order to make the most of graphene’s huge potential for electronic applications, the high quality production of layer structures on crystalline semiconductors – known as wafers – is very important. Researchers from the FAU have made a considerable contribution to this field. In 2009, Prof. Dr. Thomas Seyller developed a method whereby the highest quality graphene could be synthesized onto silicon carbide crystals. This method is considered by experts as an important step towards a graphene-based electronic circuit. In 2010 Seyller was awarded the Walter-Schottky Prize from the German Physical Society, the highest national award for outstanding research work in solid-state physics.

The next important step in terms of graphene-wafers is the production of devices. It is particularly important to find a way of controlling graphene layers for electrical applications. This is where carrier material comes into play: silicon carbide is a semiconductor, which through skillful manipulation, can be used as an integrated drive electrode. This is what Professor Dr. Heiko Weber and his team have now succeeded in doing. The FAU researchers have not just produced sample components, but have also explained in detail the physical effects that could occur when using such an electrode. With this knowledge it is now possible to tailor optimal integrated electrodes for graphene for the most diverse areas of application. The major advantage of such an electrode is obvious: the graphene layer on the surface remains freely accessible. This makes way for entirely new possibilities in both research and application, for ultra¬-sensitive sensors for example, which can even detect individual atoms.

This is one of many areas of research conducted by Erlangen researchers within the framework of the Engineering of Advanced Materials Cluster of Excellence (www.eam.uni-erlangen.de) at the Friedrich-Alexander University of Erlangen-Nürnberg.

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