Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)

O 15.59: Poster

Freitag, 4. März 2005, 17:00–20:00, Poster TU D

Construction of an Atomic Force Microscope combined with a Field Ion Microscope — •Daniel Braun, André Schirmeisen, Hendrik Hölscher, and Harald Fuchs — Physikalisches Institut, WWU Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

While the atomic force microscope (AFM) is capable of resolving surfaces with atomic resolution, the exact configuration of the tip is entirely unknown. But it is necessary to know the exact position and identity of the tip atoms to understand the contrast mechanisms in atomic force microscopy. A method that allows to determine the position of the tip atoms with atomic precision is the field ion microscope (FIM).

We build an AFM according to a design previously published [1] for operation at low temperatures under an ultra high vacuum (UHV) conditions. The construction of the microscope body features a very high mechanical stability that makes an external damping mechanism unnecessary. The original design uses a silicon cantilever as the force sensor; its bending is detected by an optical interferometer. However, it is very difficult to use conventional silicon tips in a FIM. Therefore we intend to use a tuning fork [2], which allows us to use an appropriate material, e.g. tungsten, as the tip material of the force sensor. Our goal is to investigate how the contrast mechanism in AFM is influenced by the exact geometry of the last atoms of the tip.

[1] W. Allers et al., Rev. Sci. Instrum. 69 (1998) 221

[2] F.J. Giessibl, Appl. Phys. Lett. 76 (2000) 1470