Sub-Angstrom oscillation amplitude non-contact atomic force microscopy for lateral force gradient measurement


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Atabak M., Unverdi O., Özer H. Ö. , Oral A.

APPLIED SURFACE SCIENCE, vol.256, no.5, pp.1299-1303, 2009 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 256 Issue: 5
  • Publication Date: 2009
  • Doi Number: 10.1016/j.apsusc.2009.10.026
  • Journal Name: APPLIED SURFACE SCIENCE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1299-1303
  • Keywords: Non-contact lateral atomic force microscopy, Small oscillation amplitude, Lateral force gradient-distance spectroscopy, FRICTION, SPECTROSCOPY, VANDERWAALS, SURFACES
  • Middle East Technical University Affiliated: No

Abstract

We report the first results from novel sub-Angstrom oscillation amplitude non-contact atomic force microscopy developed for lateral force gradient measurements. Quantitative lateral force gradients between a tungsten tip and Si(1 1 1)-(7 x 7) surface can be measured using this microscope. Simultaneous lateral force gradient and scanning tunnelling microscope images of single and multi atomic steps are obtained. In our measurement, tunnel current is used as feedback. The lateral stiffness contrast has been observed to be 2.5 N/mat single atomic step, in contrast to 13 N/m at multi atomic step on Si(1 1 1) surface. We also carried out a series of lateral stiffness-distance spectroscopy. We observed lateral stiffness-distance curves exhibit sharp increase in the stiffness as the sample is approached towards the surface. We usually observed positive stiffness and sometimes going into slightly negative region. (C) 2009 Elsevier B. V. All rights reserved.