Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 99: Scanning Probe Methods III
O 99.6: Vortrag
Freitag, 4. April 2014, 11:45–12:00, GER 38
Kelvin Probe Force Microscopy Studies of Lead Islands on Si(111) — •Thomas Späth1, Carmen Pérez León1, Michael Marz1, Hilbert v. Löhneysen1,2, and Regina Hoffmann-Vogel1 — 1Karlsruher Institut für Technologie (KIT), Physikalisches Institut and DFG-Center for Functional Nanostructures (CFN), D-76131 Karlsruhe — 2Karlsruher Institut für Technologie (KIT), Institut für Festkörperphysik, D-76021 Karlsruhe
Quantum size sffects (QSE) become pronounced when the thickness of a metal film approaches the de Broglie wavelength of the confined electrons. QSE lead to an oscillatory behavior of many physical properties as a function on the thickness of the metallic film. We have studied the influence of the QSE on the work function of Pb islands on Si(111). Pb was evaporated in ultra-high vacuum at room temperature on the Si(111)-7×7 surface. The height and local work function of the islands were simultaneously characterized by non-contact atomic force microscopy and Kelvin probe force microscopy. To prevent dewetting, the measurements were performed at approx. 110 K. The observed height of the islands ranges between four and nine monolayers. The local work-function difference shows an even-odd oscillatory dependence on the island’s height, in good agreement with calculations [1] and previous results [2]. The amplitude of the oscillation decreases with increasing film thickness.
[1] C. M. Wei and M. Y. Chou, Phys. Rev. B 66, 233408 (2002).
[2] J. Kim, S. Y. Qin, W. Yao, Q. Niu, M. Y. Chou, and C. K. Shih, Proc. Natl. Acad. Sci. USA 107, 12761 (2010).