Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Poster Session
MM 17.46: Poster
Montag, 26. März 2012, 17:00–19:00, Poster B
Study of field evaporation from metal tips by using a custom tunable laser-assisted field ion microscope (FIM) — •Armin Feist1,2, Johannes Endres1, Carsten Nowak2, and Claus Ropers1,2 — 1University of Göttingen, Courant Research Center Nano-Spectroscopy and X-Ray Imaging, 37077 Göttingen, Germany — 2University of Göttingen, Institute for Materials Physics, 37077 Göttingen, Germany
In the recent past, field ion microscopy (FIM) and atom probe tomography (APT) have shown their potential as versatile tools for studying materials interacting with ultrashort laser pulses at an atomic scale. In order to examine the physical processes involved in laser-assisted field evaporation from nanoscale tips, a conventional FIM was equipped with a tunable femtosecond laser system. We study the evaporation by differential image analysis in FIM mode, as opposed to direct detection of evaporated sample atoms as in APT. The advantage of this approach lies in its capability to atomically resolve the surface structure during the continuous evaporation process. Wavelength, static field and fluence dependent measurements on W and Mo yield insight into the microscopic evaporation mechanism and support thermal activation, while being inconsistent with the optical rectification model.