Professor of Materials Science and Director of the Electron Microscopy Facility. I am a Fellow of the Royal Society and a Professorial Fellow at Peterhouse.
Before moving to Cambridge in 1997, I held two Research Fellowships in the H.H. Wills Physics Laboratory at the University of Bristol, the first funded by The Royal Commission for The Exhibition of 1851 and the second by The Royal Society. I have studied a wide variety of materials by electron microscopy and developed a number of novel electron microscopy techniques. My recent research has concentrated on electron tomography, electron holography, energy filtered TEM and precession electron diffraction.
1. ELECTRON TOMOGRAPHY
3D Reconstruction of Nano-Structures. By recording a tilt series of scanning transmission electron micrographs using high angle scattering or energy filtered images using fixed beam methods it is possible to reconstruct the 3-dimensional structure and compostion of nanoscale materials.
2. ELECTRON HOLOGRAPHY
Using a field emission TEM, off-axis and in-line (Fresnel) electron holography is being used to study a variety of material properties: Electric Fields in biased and non-biased p-n junctions, metal oxide grain boundaries and ferroelectrics; Magnetic Fields in magnetic nanowires, thin film devices and small single domain particles.
3. ENERGY-FILTERED IMAGING AND DIFFRACTION
A number of new techniques have been established to improve the accuracy of core-loss (energy-filtered) imaging of mixed-phase samples. Hybrid modes, such as spectrum-imaging and w-q maps have also been used for more fundamental studies, e.g. plasmon dispersion, surface losses and Cerenkov radiation.
4. AB-INITIO STRUCTURE DETERMINATION BY ELECTRON DIFFRACTION
Using a combination of high resolution electron microscopy, conventional electron diffraction and electron precession, the structure of sub-micron particles can now be determined to an accuracy approaching that of X-ray diffraction.