Public Release: 

Seeing an atomic thickness

National Physical Laboratory

Scientists from the National Physical Laboratory (NPL), in collaboration with Linköping University, Sweden, have shown that regions of graphene of different thickness can be easily identified in ambient conditions using Electrostatic Force Microscopy (EFM).

The exciting properties of graphene are usually only applicable to the material that consists of one or two layers of the graphene sheets. Whilst synthesis of any number of layers is possible, the thicker layers have properties closer to the more common bulk graphite.

For device applications one- and two-layer graphene needs to be precisely identified apart from the substrate and regions of thicker graphene.

Exfoliated graphene sheets up to ~100 μm in size can be routinely identified by optical microscopy. However, the situation is much more complicated in the case of the epitaxial graphene grown on silicon carbide wafers with a diameter up to 5 inches where the straightforward identification of the graphene thickness is difficult using standard techniques.

This research shows that EFM, which is one of the most widely accessible and simplest implementations of scanning probe microscopy, can clearly identify different graphene thicknesses.

The technique can also be used in ambient environments applicable to industrial requirements.

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This work was recently published in Nano Letters. http://pubs.acs.org/doi/abs/10.1021/nl200581g

About NPL

The National Physical Laboratory (NPL) is one of the UK's leading science and research facilities. It is a world-leading centre of excellence in developing and applying the most accurate standards, science and technology available.

NPL occupies a unique position as the UK's National Measurement Institute and sits at the intersection between scientific discovery and real world application. Its expertise and original research have underpinned quality of life, innovation and competitiveness for UK citizens and business for more than a century:

  • NPL provides companies with access to world-leading support and technical expertise, inspiring the absolute confidence required to realise competitive advantage from new materials, techniques and technologies;

  • NPL expertise and services are crucial in a wide range of social applications - helping to save lives, protect the environment and enable citizens to feel safe and secure. Support in areas such as the development of advanced medical treatments and environmental monitoring helps secure a better quality of life for all;

  • NPL develops and maintains the nation's primary measurement standards, supporting an infrastructure of traceable measurement throughout the UK and the world, to ensure accuracy and consistency.

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