Measurements of key structural properties of graphene
The properties of graphene are determined by a complex combination of the morphology, chemistry and the electronic state of the graphene, which originate in a mixture of its intrinsic and extrinsic properties, as the material can be easily doped, or contaminated, by its interaction with the atmosphere and substrate.
Therefore, techniques need to be developed which can measure essential properties on a local scale and, most importantly, correlate these measurements with the material device performance.
The capability for real-time, in situ analysis represents a major strength of these techniques. Study of the environmental effects, such as temperature, humidity and gas composition, on the structural and mechanical properties of graphene is an additional advantage of these methods.
We aim to develop metrological methods for measurements of key structural properties of graphene, including lateral size and thickness, stiffness, deformation and defect structure.
We use the following techniques:
Atomic Force Microscopy (AFM - including force modulation, force distance and lateral force microscopy modes) for mapping the surface topography in combination with quantitative measurements of such fundamental properties as Young Modulus, deformation level and adhesion.
Scanning Tunnelling Microspcopy (STM) for imaging surfaces at the atomic level, gaining information on the electronic structure and mapping the local density of states as a function of energy within the sample.
Raman spectroscopy and microscopy techniques for identifying and mapping the number and orientation of layers, defects, contamination and doping of surfaces, with up to 10 nm lateral resolution using tip-enhanced Raman spectroscopy (TERS). They will be applied for studies of surface morphology and structure and quantitative nanomechanical properties.