Scanning transmission electron microscopy*

Crewe, A. V.

doi:10.1111/j.1365-2818.1974.tb03937.x

Cited by 56 publications

(23 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An important prerequisite for the development of analytical TEM was the development of the so-called scanning transmission electron microscope (STEM), where the specimen is scanned in a raster point-by-point with a small electron probe [3]. Although the lateral point resolution, mainly influenced by the probe size, the source brightness, the sample thickness and -as a result -by the signal-to-noise ratio of the electron microscopic image, does not exceed 0.5 nm, the STEM became a powerful tool because of the possible combination with analytical techniques such as microdiffraction, energy-dispersive Xray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS).…”

Section: Introductionmentioning

confidence: 99%

Thin film analysis in the nanometer scale

Wetzig

Bauer

1996

Analytical and Bioanalytical Chemistry

View full text Add to dashboard Cite

A survey is presented on the present state of the art in analytical transmission electron microscopy (ATEM). An essential advantage of this method is the simultaneous use of imaging, analytical and microdiffraction techniques with a lateral resolution in the 1.5 nm range. Two different analytical techniques are frequently used as ATEM attachments, energy dispersive X-ray spectrometry (EDXS) and electron energy loss spectrometry (EELS). Microscopic images with nanometer resolution may be also produced by energy selected imaging (ESI) with characteristic energy loss electrons. Advantages and limitations of all these methods will be discussed using actual material problems in the field of thin film research.

show abstract

Section: Introductionmentioning

confidence: 99%

Thin film analysis in the nanometer scale

Wetzig

Bauer

1996

Analytical and Bioanalytical Chemistry

View full text Add to dashboard Cite

show abstract

“…As can be appreciated from [4] and [6], the theoretical resolution r0, [5 ], can only be approached for very large fl.…”

mentioning

confidence: 99%

“…The considerations leading to the optimum parameters and the resulting performance in the scanning transmission electron microscope have been recently reviewed by A. V. Crewe (6) and E. Zeitler (7). We have extended the analysis of these authors to the case of a proton probe (8).…”

mentioning

confidence: 99%

“…As discussed in ref. 6, the probe current at the focused spot, at overall accelerating voltage V and semi-angle of incidence aj, is (nonrelativistically) Jo = 07r2a,262AP2V…”

mentioning

confidence: 99%

“…How closely the theoretical microscope resolution can be approached in practice depends essentially on the specific brightness of the ion (or electron) source, since the probe current must exceed that required to obtain an intelligible picture in a practicable scan time. We consider a microscope consisting of a source of radius 6 and an imaging lens of overall magnification M, spherical aberration coefficient C8, and chromatic aberration coefficient Co. We also assume that the source yields ions with energy spread eAV and that its specific brightness j3 is ,B = I/r2a262V, [1] where I is the primary current, a the half-angle of emission, and V1 the source voltage. As discussed in ref.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Scanning transmission ion microscope with a field ion source.

Escovitz¹,

Fox²,

Levi‐Setti³

1975

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Experiments with a low-resolution scanning transmission ion microscope, using hydrogen ions from a field ionization source, indicate that it will be feasible by this approach to aim at high-resolution ion microscopy. Micrographs of unstained biological specimens have been obtained by critical range absorption of a 55 keV hydrogen ion beam at a resolution of 2000 A.As a first step toward the development of a high-resolution scanning transmission ion microscope, we have constructed and operated a 65 kV prototype ion-gun scanning transmission ion microscope which accelerates and focuses hydrogen ions from a field ionization (1) source. Our aim is to emulate and complement the achievements of scanning transmission electron microscopy (2), ultimately at comparable resolution, by taking advantage of the interaction properties of fast ions with matter (3). The latter include processes such as charge exchange and molecular ion dissociation which should result in contrast mechanisms unavailable to the electron microscope.We present here experimental data that are relevant to the feasibility of a high-resolution scanning transmission ion microscope and show the first low-resolution images of biological specimens obtained with the prototype instrument.Previous attempts at using ions, and in particular protons, to make images of small objects with conventional electron microscope optics have been reviewed by Grivet (4) and more recently by Levi-Setti (3). The aim was to obtain higher resolution than with electrons. This was believed to be possible because of the ion's shorter De Broglie wavelength. The potential of proton charge exchange as a possible new source of contrast was recognized by Chanson and Magnan (5).Several factors, however, conspired to abort this development of the proton microscope as a high-resolution and viable instrument. In our view, the principal limitations originated in the approach of conventional microscopy itself, where the large rate of proton energy loss (10-30 eV/A in traversing organic materials at 100 keV) causes irreparable chromatic aberration. For this reason, we have chosen the approach of scanning transmission microscopy, where no optics is affected by the beam-specimen interaction so that the latter can be used to advantage in producing contrast.The considerations leading to the optimum parameters and the resulting performance in the scanning transmission electron microscope have been recently reviewed by A. V. Crewe (6) and E. Zeitler (7). We have extended the analysis of these authors to the case of a proton probe (8). The basic problem consists of optimizing the design parameters to obtain the maximum probe current in the smallest beam spot. How closely the theoretical microscope resolution can be approached in practice depends essentially on the specific brightness of the ion (or electron) source, since the probe current must exceed that required to obtain an intelligible picture in a practicable scan time. We consider a microscope consisting of a source of radius 6 and an ...

show abstract

Recent Advances of 2D Materials in Nonlinear Photonics and Fiber Lasers

Liu

et al. 2020

Advanced Optical Materials

135

View full text Add to dashboard Cite

The explosive success of graphene opens a new era of ultrathin 2D materials. It has been realized that the van der Waals layered materials with atomic and less atomic thickness can not only exist stably, but also exhibit unique and technically useful properties including small size effect, surface effect, macro quantum tunnel effect, and quantum effect. With the extensive research and revealing of the basic optical properties and new photophysical properties of 2D materials, a series of potential applications in optical devices have been continuously demonstrated and realized, which immediately roused an upsurge of study in the academic circle. Therefore, the application of 2D materials as broadband, efficient, convenient, and versatile saturable absorbers in ultrafast lasers is a potential and promising field. Herein, the main preparation methods of 2D materials are reviewed and technical guidelines for identifying and characterizing layered 2D materials are provided. After investigating the characteristics of 2D materials thoroughly in nonlinear optics, their performances in fiber lasers are comprehensively summarized according to the types of materials. Finally, some developmental challenges, potential prospects, and future research directions are summarized and presented for such promising materials.

show abstract

Scanning transmission electron microscopy*

Cited by 56 publications

References 13 publications

Thin film analysis in the nanometer scale

Thin film analysis in the nanometer scale

Scanning transmission ion microscope with a field ion source.

Recent Advances of 2D Materials in Nonlinear Photonics and Fiber Lasers

Contact Info

Product

Resources

About