S.J. Haigh, A. Rooney, E. Prestat, E. Khestanova, R. Dryfe, M Velický, R.V. Gorbachev, R. Boya, Y. Cao, I. Grigorieva, R. Nair, K. Novoselov, F. Withers, A.K. Geim, National Graphene Institute, University of Manchester, Manchester, M13 9PL, UK
2D crystals can be layered together to create new van der Waals crystals with bespoke properties. However, the performance of such materials is strongly dependent on the quality of the crystals and their interfaces at the atomic scale. Transmission electron microscopy (TEM) is the only technique able to characterize the nature of buried interfaces in these engineered van der Waals crystals and hence to provide insights into the optical, electronic and mechanical properties. I will report the use of TEM imaging technique to aid the development of 2D heterostructures. I will review our work on traditional heterostructures as well as those where individual planes of atoms have been effectively removed to produce nanochannels. The latter provide unique opportunities to help understand water flow at the nanoscale. I will show the use of TEM to reveal how high pressure confinement in such channels can drive chemical transformations in aqueous salts . I will further demonstrate the use of STEM characterization to understand the unusual structure of Franckeite, a natural mineral phase composed of incommensurate 2D layers, which has promising electrochemical properties when exfoliated to few-layer thickness .
1. Boya et al, Nature, 538, (2016) p. 222.
2. Vasu et al, Nature Communications, 7, (2016), 12168.
3. Velický et al, Nature Communications, 8, (2017), 14410.
Sarah Haigh is a Reader in Material Science and Director of the Electron Microscopy Centre at the University of Manchester, UK. Her research interests focus on improving our understanding of nanomaterials properties using transmission electron microscope (TEM) imaging and analysis techniques. She worked as consultant application specialist to JEOL UK before moving to Manchester in 2010. She completed her PhD in 2008 at the University of Oxford working on developing exit wave reconstruction in the TEM. She now leads a research group (5 PhD student, 6 MSc Students and 3 postdocs) centred on TEM imaging of nanomaterials. She has a particular interest in imaging of materials under more realistic environments and was recently awarded an ERC starter grant to develop this area of microscopy. She has more than 100 peer reviewed papers of which 78 are from the last 3 years. She is Chair of the Institute of Physics EMAG group, a member of council for the Royal Microscopy Society (UK) and a freeman of the Worshipful Company of Armourers and Brasiers. Awards include the IOM3 Silver Award (2014), RMS Medal for Innovation in Applied Microscopy (2016) and Rosenhain Medal (2017),