Bright-field imaging of compound semiconductors using aberration-corrected scanning transmission electron microscopy

Toshihiro Aoki, Jing Lu, Martha McCartney, David Smith

Research output: Contribution to journalArticle

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Abstract

This study reports the observation of six different zincblende compound semiconductors in [110] projection using large-collection-angle bright-field (LABF) imaging with an aberration-corrected scanning transmission electron microscope. Phase contrast is completely suppressed when the collection semi-angle is set equal to the convergence semi-angle and there are no reversals in image contrast with changes in defocus or thickness. The optimum focus for imaging closely separated pairs of atomic columns ('dumbbells') is unique and easily recognized, and the positions of atomic columns occupied by heavier atoms always have darker intensity than those occupied by lighter atoms. Thus, the crystal polarity of compound semiconductors can be determined unambiguously. Moreover, it is concluded that the LABF imaging mode will be highly beneficial for studying other more complicated heterostructures at the atomic scale.

Original languageEnglish (US)
Article number094002
JournalSemiconductor Science and Technology
Volume31
Issue number9
DOIs
StatePublished - Jul 25 2016

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Keywords

  • aberration-corrected electron microscopy
  • compound semiconductor
  • crystal polarity
  • large-angle bright-field imaging

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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