An Atomic Study of the Interaction of Oxygen and Strained Cu Films

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An Atomic Study of the Interaction of Oxygen and
Strained Cu Films
Juan de la Figuera, Karsten Pohl, Andreas K.
Schmid, Norm C. Bartelt Jan Hrbek and Robert
Q. Hwang
Sandia National Laboratories on leave
fromUniversidad Complutense de Madrid
Brookhaven National Laboratory
Funding DOE-AC04-94AL85000 Fulbright-MEC
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Goals and Approach

• Study the initial stages of the corrosion of
  strained metal films
• Select a strained film whose atomic structure is
  completely known Cu/Ru(0001)
• The reactivity of the surface will be linked with
  the preexisting dislocation structure, and with
  how it can be modified.

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2 ML of Cu/Ru(0001)
150nm x100nm
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HCP and FCC separated by Shockley Partial
Dislocations
HCP
FCC
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Edge Dislocations Meeting point of Shockley
Partials
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2ML Cu/Ru(0001) Network of Shockley Partials and
Edge Dislocations
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Oxygen exposure of Cu/Ru(0001) film
After 0.9 L
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Decoration of edge dislocations
Exposures above 0.05L
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Nucleation of a pair of edge dislocations
FCC
Exposures above 0.5 L
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Formation of a trigon
Exposure above 0.9 L
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Sequence of effects of Oxygen
0L
0.6L
0.9L
2.4L
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Ordered network of trigons with Sulfur
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First stage of exposure to Sulfur
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Formation of the ordered trigons with Sulfur
FCC
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Summary

• We have studied the response of annealed Cu films
  on Ru(0001) to exposure of S and O2 at RT using
  STM
• The structural response of this strained film is
  determined by the reactivity of edge
  dislocations
• With increasing exposure
• Reaction with preexisting edge dislocations
• Generation of new edge dislocations