Graphene is a material consisting of only one layer of carbon atoms, arranged in a hexagonal pattern, which gives it a number of unique properties. It is 200 times stronger than steel, conducts electricity better than any other material, and can detect single molecules on its surface. Since the discovery of graphene – which resulted in a Nobel Prize in 2010 – the EU has invested EUR 1 billion in a graphene flagship project which is to accelerate its development towards industrial applications. Applications of graphene on silicon carbide include biosensors and high-speed electronics.
Swedish graphene supplier Graphensic has developed a patented method of producing graphene on silicon carbide.
“When silicon carbide is heated up, it moves into the gaseous phase, resulting in a residual layer of carbon atoms as the silicon leaves the surface”, explains Mikael Syväjärvi, co-founder of Graphensic. “Our customers today are mainly involved in research, but companies are starting to show an interest. I expect it will take between five and ten years before graphene is used in common electronic products, while sensors could emerge earlier. In Sweden there is a graphene agenda that wants to position Sweden among the top ten countries in the world using graphene industrially”.
The increased demand for this new supermaterial puts pressure on production. Graphensic is currently producing 50 millimetre wafers, but will soon be able to start production of wafers with twice that diameter.
“The production of an atom-thick layer requires extreme precision and the process must of course also be repeatable. Our measurements at MAX IV Laboratory aimed to characterise our material on the basis of various production parameters by studying it in a completely controlled environment, using a powerful instrument to which we otherwise have no access.”
“Studying a material like graphene, which is only as thick as one atom, is extremely demanding on the analytical instruments. MAX IV Laboratory had both the measurement instruments and the knowledge required to obtain the information we needed. It has helped us to quality assure the process, and has led to the introduction of better production procedures.”
In addition to obtaining a better picture of the evenness and quality of the material in its production process, Mikael Syväjärvi gained information from the experiments that could be fed back into Graphensic’s procedures.
“I learned that, when stored, the material was able to absorb molecules from the surrounding air. This is not a process of oxidation, which happens with many common materials, but rather that the molecules can rest in patches on the surface. These can be removed simply by warming up the material and we can now recommend this process to our clients if they store the products for a long time.”
Graphensic used the SPELEEM instrument at the I311 beamline at MAX IV Laboratory. SPELEEM stands for Spectroscopic PhotoEmission and Low Energy Electron Microscope, and offers researchers the possibility to produce both microscopical images with nanometre precision of various materials, and at the same time study the chemical, structural and electronic properties of the surfaces.