Scanning Electron Microscopes: Is High Resolution Possible?

Abstract

Experiments with this scanning microscope have produced extremely encouraging results so that we feel Confident in predicting high resolution and high contrast after some obvious modifications are made in the system, such as providing a good objective lens. Experience with conventional lenses indicates that the instrument behaves in a predictable manner and there is no reason to doubt that the resolution can be as good as that of a conventional microscope. The use of quadrupole lenses will depend on calculations now being performed. There is cause for optimism; high resolution may also be possible with this kind of lens. Experience with field emission shows that the technology is not difficult and that there is more than enough current available for any conceivable use. Energy-loss measurements have been made on a variety of materials. It is attractive to consider the possibility of chemical analysis of selected areas of a specimen. We believe that a very crude form of analysis may indeed be possible. The principal advantage of the use of energy-loss techniques, however, may be in the availability of another contrast mechanism. The ability to "see" small details may be considerably enhanced. Finally, we are experimenting with the possibility of using transmitted electrons of different energy losses to produce different colors on a color television display. This should add an extra element to the picture contrast which may be of some value.

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

“…However, there were many technical difficulties (mostly limited by noise) of STEM and then most of efforts were dedicated on the development of TEM. In the late 1960s, A. Crewe newly designed and constructed STEM with a field emission gun, annular detector and spectrometer for EELS, where the transmitted electrons through the center hole of annular detector were collected by the EELS spectrometer [153]. The basic design of modern STEM is referred to Crewe's microscope.…”

Aberration‐free images observed with TEM and STEM

“…the bright-field imaging mode that Crewe developed originally. 21 In these cases, however, the STEM observation should have the same disadvantages as those of the conventional TEM. This situation can be understood easily with the reciprocity theorem, as Zeitler and Thomson pointed out.…”

Aberration-Corrected Electron Microscopy of Nanoparticles

“…Cosslett proposed in 1965 that the use of a ring-shaped detector would improve the differentiation of elements present in the TEM sample [23]. A year later, Crewe reaches a resolution of 50 Å using a field emission gun [24]. Two years later, Crewe sets a new resolution record at 30 Å [25].…”