Single atom sputtering events Direct observation of near-surface depleted zones in ion-irradiated tungsten

Michael I. Current, Ching Yeu Wei, David N. Seidman

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

The three-dimensional spatial arrangement of vacancies contained in depleted zones (DZs) of ion-irradiated tungsten specimens, has been determined with atomic resolution by the field-ion microscope (FIM) technique. These DZs were detected in the near-surface region of specimens which had been irradiated in situ at ⩽ 15 K with 20 keV W+, 30 keV W+, Kr+, Cu+ or Ar+ ions. The values of the ion dose employed were small (⩽ 1013 ions cm−2); therefore, each DZ analysed was the result of the impact of a single projectile ion. At the irradiation temperature (⩽ 15 K) both the self-interstitial atoms and vacancies were immobile, so that the primary state of radiation damage was preserved. The following properties of each DZ were determined: (1) the total number of vacancies; (2) the number of vacancies in the near-surface region; (3) the spatial extent-that is, the dimensions required to determine a volume; (5) the average vacancy concentration associated with the near-surface region; (6) the first-nearest-neighbour cluster distribution for the vacancies in the near-surface region; (7) the radial distribution function of all the vacancies; (8) the distribution of vacancies as a function of depth normal to the irradiated surface; and (9) the sputtering yield, Most of the above properties of the near-surface DZs had similar values to those of the DZs detected in the bulk of the FIM specimens. The total number of vacancies detected in the near-surface region was approximately consistent with theoretical estimates of the average sputtering yield. The sputtering yield of individual DZs exibited significant fluctuations from the measured average sputtering yield.

Original languageEnglish (US)
Pages (from-to)103-138
Number of pages36
JournalPhilosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties
Volume43
Issue number1
DOIs
StatePublished - Jan 1981

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Science(all)
  • Condensed Matter Physics
  • Physics and Astronomy (miscellaneous)
  • Metals and Alloys

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