Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


In this short review we contrast and compare the relative merits of three imaging techniques in the CTEM and STEM, for detecting subnanometer size catalyst clusters. It is shown that incoherent dark field signals, such as those obtained by hollow-cone illumination in the CTEM, and the annular detector in the STEM, are significantly more sensitive to subnanometer size clusters than the bright field signal. Sensitivity to clusters of high atomic number increases as the illumination (or detector) semi-angle increases, although at the expense of decreased signal-to-noise. The STEM annular detector signal offers advantages over the CTEM hollow-cone signal in this respect since it has a higher electron collection efficiency. A further advantage of the STEM is that image contrasts may be enhanced by electronically combining the annular detector signal with the axial energy loss signal. This ratio method, or Z contrast technique, has been used with success to detect single Pt atoms on thin low atomic number supports.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposia Proceedings
PublisherMaterials Research Soc
Number of pages12
ISBN (Print)0931837278
StatePublished - Dec 1 1986
Externally publishedYes

Publication series

NameMaterials Research Society Symposia Proceedings
ISSN (Print)0272-9172

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


Dive into the research topics of 'DETECTION AND IMAGING OF SUPPORTED CATALYST PARTICLES.'. Together they form a unique fingerprint.

Cite this