Imaging of radiation-sensitive samples in transmission electron microscopes equipped with Zernike phase plates

Marek Malac, Marco Beleggia, Ray Egerton, Yimei Zhu

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We have optimized a bright-field transmission electron microscope for imaging of high-resolution radiation-sensitive materials by calculating the imaging dose n0 needed to obtain a signal–to-noise ratio (SNR)=5. Installing a Zernike phase plate (ZP) decreases the dose needed to detect single atoms by as much as a factor of two at 300kV. For imaging larger objects, such as Gaussian objects with full-width at half-maximum larger than 0.15nm, ZP appears more efficient in reducing the imaging dose than correcting for spherical aberration. The imaging dose n0 does not decrease with extending of chromatic resolution limit by reducing chromatic aberration, using high accelerating potential (U0=300kV), because the image contrast increases slower than the reciprocal of detection radius. However, reducing chromatic aberration would allow accelerating potential to be reduced leading to imaging doses below 10e−/Å2 for a single iodine atom when a CS-corrector and a ZP are used together. Our simulations indicate that, in addition to microscope hardware, optimization is heavily dependent on the nature of the specimen under investigation.
Original languageEnglish
JournalULTRAMICROSCOPY
Volume108
Issue number2
Pages (from-to)126-140
Number of pages15
ISSN0304-3991
DOIs
Publication statusPublished - 2008
Externally publishedYes

Keywords

  • Zernike phase plate
  • Boersch lens
  • Radiation damage
  • Transmission electron microscope
  • Spherical aberration
  • High-resolution TEM
  • Biological TEM
  • Single molecule TEM
  • Low-voltage TEM

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