Albert Victor Crewe was a British-born American physicist and inventor of the modern scanning transmission electron microscope capable of taking still and motion pictures of atoms, a technology that provided new insights into atomic interaction and enabled significant advances in and had wide-reaching implications for the biomedical, semiconductor, and computing industries.
Crewe (right, facing camera) explains the ZGS's Cockroft-Walton preaccelerator.
Scanning transmission electron microscopy
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.
An ultrahigh-vacuum STEM equipped with a 3rd-order spherical aberration corrector
Inside the aberration corrector (hexapole-hexapole type)
Schematic of a STEM with aberration corrector
Atomic resolution imaging of SrTiO3, using annular dark field (ADF) and annular bright field (ABF) detectors. Overlay: strontium (green), titanium (grey) and oxygen (red)