We report on the automatic alignment of a transmission electron microscope equipped with an orbital angular momentum sorter using a convolutional neural network. The neural network is able to control all relevant parameters of both the electron-optical setup of the microscope and the external voltage source of the sorter without input from the user. It can compensate for mechanical and optical misalignments of the sorter, in order to optimize its spectral resolution. The alignment is completed over a few frames and can be kept stable by making use of the fast fitting time of the neural network.

Planar defects in a polycrystalline diamond film were studied by high-resolution transmission electron microscopy (HRTEM) and high-resolution scanning transmission electron microscopy (STEM). In both modes, sub-Ångström resolution was achieved by making use of two aberration-corrected systems; a TEM and a STEM CS-corrected microscope, each operated at 300 kV. For the first time, diamond in 〈110〉 zone-axis orientation was imaged in STEM mode at a resolution that allows for resolving the atomic dumbbells of carbon at a projected interatomic distance of 89 pm. Twin boundaries that show approximately the Σ3 CSL structure reveal at sub-Ångström resolution imperfections; that is, local distortions, which break the symmetry of the ideal Σ3 type twin boundary, are likely present. In addition to these imperfect twin boundaries, voids on the atomic level were observed. It is proposed that both local distortions and small voids enhance the mechanical toughness of the film by locally increasing the critical stress intensity factor.

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

A new transmission electron microscope equipped with a monochromator and a high resolution energy-filter was used for the first time to fully exploit the chemical bonding information contained in the near edge fine structures (ELNES) of electron energy-loss spectra. The instrument is capable of acquiring spectra with an energy resolution in the range of 0.1 eV, thus opening up the way for improved ELNES information. ELNES spectra of TiO2 and CoO have been recorded and are compared with data obtained with a conventional microscope and with x-ray absorption spectroscopy. In case of the L2,3 edges of the transition metals the new instrument revealed previously unobservable fine structure details, but for the O K edges the improved energy resolution does not result in more detailed structural features than observable in common microscopes. Furthermore, the potential of the new microscope to obtain chemical bonding information at the nanometer scale is discussed.