Peter Nellist | |
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| Known for | Electron microscopy |
| Academic background | |
| Alma mater | University of Cambridge |
| Doctoral advisor | John Rodenburg |
| Academic work | |
| Discipline | Materials Science |
| Institutions | |
| Website | Official website  |
Peter David Nellist, FRS is a British physicist and materials scientist, currently a professor in the Department of Materials at the University of Oxford. He is noted for pioneering new techniques in high-resolution electron microscopy. [1]
Nellist gained his B.A. (1991), M.A. (1995) and Ph.D (1996) from St John's College, Cambridge, and studied at the Cavendish Laboratory with John Rodenburg, before taking up post-doctoral research at Oak Ridge National Laboratory (ORNL) in Tennessee with ex-Cavendish researcher Stephen Pennycook. [2] Eighteen months later, Nellist returned to Cambridge on a Royal Society University Research Fellowship, which he transferred to the University of Birmingham. He left academia for four years to work for another ex-Cambridge microscopy pioneer, Ondrej Krivanek, at Nion, his newly formed company in Seattle. Nellist then returned to Trinity College Dublin and finally to the University of Oxford, where he became Joint Head of the Department of Materials in 2019. [3] [4] [5]
Nellist's research focuses on scanning transmission electron microscopy and its use in materials science. In particular, he is noted for work on electron ptychography, quantitative image interpretation, and the development of corrective electron microscope lenses, [1] [6] which he describes as "like spectacles for a microscope". [5]
In the mid-1990s, working with John Rodenburg at the Cavendish Laboratory in Cambridge, he helped to devise new ways of improving the resolution of both scanning electron microscopes and transmission electron microscopes. [7] [8]
In 1998, working with Stephen Pennycook of ORNL, he recorded "the highest resolution microscope images ever made of crystal structures". [9] [10] Six years later, Nellist, Pennycook, and colleagues at ORNL produced the first images of atoms in a crystal on sub-Angstrom scales by using a new technique to correct the optical aberrations in a scanning transmission electron microscope. [11] [12]
Nellist has won many awards, including the 2007 Burton Medal from the Microscopy Society of America for "an exceptional contribution to microscopy", the 2013 Ernst Ruska Prize from the German Electron Microscopy Society for the development of confocal electron microscopy, the 2013 Birks Award from the Microbeam Analysis Society, and the 2016 and 2020 European Microscopy Society prizes for best published paper in materials science. He was elected a Fellow of the Royal Society in 2020. He is the vice-president of the Royal Microscopical Society (of which he was also made an Honorary Fellow in 2020) [13] and a board member of the European Microscopy Society. [3] [5]
An electron microscope is a microscope that uses a beam of electrons as a source of illumination. They use electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing them to produce magnified images or electron diffraction patterns. As the wavelength of an electron can be up to 100,000 times smaller than that of visible light, electron microscopes have a much higher resolution of about 0.1 nm, which compares to about 200 nm for light microscopes. Electron microscope may refer to:
Cathodoluminescence is an optical and electromagnetic phenomenon in which electrons impacting on a luminescent material such as a phosphor, cause the emission of photons which may have wavelengths in the visible spectrum. A familiar example is the generation of light by an electron beam scanning the phosphor-coated inner surface of the screen of a television that uses a cathode ray tube. Cathodoluminescence is the inverse of the photoelectric effect, in which electron emission is induced by irradiation with photons.
Electron energy loss spectroscopy (EELS) is a form of electron microscopy in which a material is exposed to a beam of electrons with a known, narrow range of kinetic energies. Some of the electrons will undergo inelastic scattering, which means that they lose energy and have their paths slightly and randomly deflected. The amount of energy loss can be measured via an electron spectrometer and interpreted in terms of what caused the energy loss. Inelastic interactions include phonon excitations, inter- and intra-band transitions, plasmon excitations, inner shell ionizations, and Cherenkov radiation. The inner-shell ionizations are particularly useful for detecting the elemental components of a material. For example, one might find that a larger-than-expected number of electrons comes through the material with 285 eV less energy than they had when they entered the material. This is approximately the amount of energy needed to remove an inner-shell electron from a carbon atom, which can be taken as evidence that there is a significant amount of carbon present in the sample. With some care, and looking at a wide range of energy losses, one can determine the types of atoms, and the numbers of atoms of each type, being struck by the beam. The scattering angle can also be measured, giving information about the dispersion relation of whatever material excitation caused the inelastic scattering.
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a detector such as a scintillator attached to a charge-coupled device or a direct electron detector.
Transmission Electron Aberration-Corrected Microscope (TEAM) is a collaborative research project between four US laboratories and two companies. The project's main activity is design and application of a transmission electron microscope (TEM) with a spatial resolution below 0.05 nanometers, which is roughly half the size of an atom of hydrogen.
A scanning transmission electron microscope (STEM) is a type of transmission electron microscope (TEM). Pronunciation is [stɛm] or [ɛsti:i:ɛm]. As with a conventional transmission electron microscope (CTEM), images are formed by electrons passing through a sufficiently thin specimen. However, unlike CTEM, in STEM the electron beam is focused to a fine spot which is then scanned over the sample in a raster illumination system constructed so that the sample is illuminated at each point with the beam parallel to the optical axis. The rastering of the beam across the sample makes STEM suitable for analytical techniques such as Z-contrast annular dark-field imaging, and spectroscopic mapping by energy dispersive X-ray (EDX) spectroscopy, or electron energy loss spectroscopy (EELS). These signals can be obtained simultaneously, allowing direct correlation of images and spectroscopic data.
The Department of Materials at the University of Oxford, England was founded in the 1950s as the Department of Metallurgy, by William Hume-Rothery, who was a reader in Oxford's Department of Inorganic Chemistry. It is part of the university's Mathematical, Physical and Life Sciences Division
Michael A. O'Keefe is a physicist who has worked in materials science and electron microscopy. He is perhaps best known for his production of the seminal computer code for modeling of high-resolution transmission electron microscopy (HRTEM) images; his software was later made available as part of the DeepView package for remote electron microscopy and control. O'Keefe's tutorial on theory and application of high-resolution electron microscope image simulation is available online.
Annular dark-field imaging is a method of mapping samples in a scanning transmission electron microscope (STEM). These images are formed by collecting scattered electrons with an annular dark-field detector.
High-resolution transmission electron microscopy is an imaging mode of specialized transmission electron microscopes that allows for direct imaging of the atomic structure of samples. It is a powerful tool to study properties of materials on the atomic scale, such as semiconductors, metals, nanoparticles and sp2-bonded carbon. While this term is often also used to refer to high resolution scanning transmission electron microscopy, mostly in high angle annular dark field mode, this article describes mainly the imaging of an object by recording the two-dimensional spatial wave amplitude distribution in the image plane, similar to a "classic" light microscope. For disambiguation, the technique is also often referred to as phase contrast transmission electron microscopy, although this term is less appropriate. At present, the highest point resolution realised in high resolution transmission electron microscopy is around 0.5 ångströms (0.050 nm). At these small scales, individual atoms of a crystal and defects can be resolved. For 3-dimensional crystals, it is necessary to combine several views, taken from different angles, into a 3D map. This technique is called electron tomography.
JEOL, Ltd. is a major developer and manufacturer of electron microscopes and other scientific instruments, industrial equipment and medical equipment.
Nestor J. Zaluzec is an American scientist and inventor who works at Argonne National Laboratory. He invented and patented the Scanning Confocal Electron Microscope. and the π Steradian Transmission X-ray Detector for Electron-Optical Beam Lines and Microscopes.
Ptychography is a computational method of microscopic imaging. It generates images by processing many coherent interference patterns that have been scattered from an object of interest. Its defining characteristic is translational invariance, which means that the interference patterns are generated by one constant function moving laterally by a known amount with respect to another constant function. The interference patterns occur some distance away from these two components, so that the scattered waves spread out and "fold" into one another as shown in the figure.
Scanning confocal electron microscopy (SCEM) is an electron microscopy technique analogous to scanning confocal optical microscopy (SCOM). In this technique, the studied sample is illuminated by a focussed electron beam, as in other scanning microscopy techniques, such as scanning transmission electron microscopy or scanning electron microscopy. However, in SCEM, the collection optics are arranged symmetrically to the illumination optics to gather only the electrons that pass the beam focus. This results in superior depth resolution of the imaging. The technique is relatively new and is being actively developed.
Transmission electron microscopy DNA sequencing is a single-molecule sequencing technology that uses transmission electron microscopy techniques. The method was conceived and developed in the 1960s and 70s, but lost favor when the extent of damage to the sample was recognized.
Ondrej L. Krivanek is a Czech/British physicist resident in the United States, and a leading developer of electron-optical instrumentation. He won the Kavli Prize for Nanoscience in 2020 for his substantial innovations in atomic resolution electron microscopy.
Sergei V. Kalinin is a corporate fellow at the Center for Nanophase Materials Sciences (CNMS) at Oak Ridge National Laboratory (ORNL). He is also the Weston Fulton Professor at the Department of Materials Science and Engineering at the University of Tennessee-Knoxville.
John Marius Rodenburg is emeritus professor in the Department of Electronic and Electrical Engineering at the University of Sheffield. He was elected a Fellow of the Royal Society (FRS) in 2019 for "internationally recognised... work on revolutionising the imaging capability of light, X-ray and electron transmission microscopes".
Convergent beam electron diffraction (CBED) is an electron diffraction technique where a convergent or divergent beam of electrons is used to study materials.
4D scanning transmission electron microscopy is a subset of scanning transmission electron microscopy (STEM) which utilizes a pixelated electron detector to capture a convergent beam electron diffraction (CBED) pattern at each scan location. This technique captures a 2 dimensional reciprocal space image associated with each scan point as the beam rasters across a 2 dimensional region in real space, hence the name 4D STEM. Its development was enabled by evolution in STEM detectors and improvements computational power. The technique has applications in visual diffraction imaging, phase orientation and strain mapping, phase contrast analysis, among others.
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