Performance of low-voltage STEM/TEM with delta corrector and cold field emission gun

Abstract

To reduce radiation damage caused by the electron beam and to obtain high-contrast images of specimens, we have developed a highly stabilized transmission electron microscope equipped with a cold field emission gun and spherical aberration correctors for image- and probe-forming systems, which operates at lower acceleration voltages than conventional transmission electron microscopes. A delta-type aberration corrector is designed to simultaneously compensate for third-order spherical aberration and fifth-order 6-fold astigmatism. Both were successfully compensated in both scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM) modes in the range 30-60 kV. The Fourier transforms of raw high-angle annular dark field (HAADF) images of a Si[110] sample revealed spots corresponding to lattice spacings of 111 and 96 pm at 30 and 60 kV, respectively, and those of raw TEM images of an amorphous Ge film with gold particles showed spots corresponding to spacings of 91 and 79 pm at 30 and 60 kV, respectively. Er@C(82)-doped single-walled carbon nanotubes, which are carbon-based samples, were successfully observed by HAADF-STEM imaging with an atomic-level resolution.

Inelastic electron irradiation damage in hexagonal boron nitride

“…High-resolution imaging and chemical analysis were performed using a Jeol JEM-2100F microscope, fitted with a cold field-emission gun, dodecapole-based aberration correctors (Jeol) and electron energy spectrometer (Gatan), operated at 60 and 30 kV (Sasaki et al, 2010). Throughout the course of the experiments, the temperature of the samples was varied while inside the microscope, under vacuum, using either a LN 2 holder (Gatan, for low-temperature), a filament-based heating holder (Jeol, for intermediate temperatures) or a MEMS-based resistive heating holder (Protochips, for high temperatures).…”

Achieve atomic resolution in in situ S/TEM experiments to examine complex interface structures in nanomaterials

“…Dedicated S/TEM machines are proposed, e.g. when focusing on low voltage investigation [83,136,137]. At the same time, there is ongoing progress in enhancing S/N and contrast in atomic scale images while lowering electron dose (rates), such as drift corrected frame averaging [169], NCSI [61], in-line holography [12,55,63], integrated differential phase contrast (iDPC) [88], ptychography [122], supported by simultaneous development of innovative detection schemes and systems [13,50,117,122,151].…”

Higher-order aberration corrector for an image-forming system in a transmission electron microscope

“…In this study, we applied the corrector to image-forming and evaluated the aberration correction capability at 60 kV. Experimental observation is demonstrated in our literature [17], showing atomic-resolution images in TEM at 60 and 30 kV.…”