Standardization

Recent research by NPL, Oxford Instruments, Chalmers University and Graphensic has enabled the quantum Hall effect to be realized at both lower magnetic fields and higher temperatures, whilst still retaining part per billion accuracies.

The long-term collaboration between NPL, Chalmers University of Technology and Graphensic has resulted in a big advance in graphene samples. Epitaxial graphene (epigraphene) has been grown on silicon carbide and has better performance at higher temperatures and lower magnetic field than was previously possible. In practical terms, it has also removed the difficult process of fine-tuning the carrier density and means the ‘table-top’ system can be warmed up and cooled back down and the plateau stays where it is set with no user intervention.

Researchers from the National University of Singapore (NUS) have set out to tackle the issue of a lack of graphene production standards, which leads to many cases of poor quality graphene from suppliers. The team developed a systematic and reliable method for establishing the quality of graphene samples from around the world. They were able to achieve this by using a wide range of analytical techniques and tested samples from many suppliers.

Upon analyzing samples from over 60 different providers from the Americas, Asia, and Europe, the NUS team discovered that the majority contained less than 10% of what can be considered graphene flakes. The bulk of the samples was graphite powder that was not exfoliated properly.