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Vorträge und Posterpräsentationen (mit Tagungsband-Eintrag):

R. Ritter, R.A. Wilhelm, M. Stöger-Pollach, A. Mücklich, U. Werner, A. Beyer, S. Facsko, A. Gölzhäuser, F. Aumayr:
"Nano-holes milled in 1 nm thick carbon nanomembranes with slow highly charged ions";
Poster: 19th International Workshop on Inelastic Ion-Surface Collisions (IISC-19), Frauenchiemsee/Germany; 18.09.2012; in: "Book of Abstracts, 19th International Workshop on Inelastic Ion-Surface Collisions (IISC-19)", (2012), S. 32.



Kurzfassung englisch:
1. INTRODUCTION
We have recently discovered that the impact of individual
slow highly charged ions (HCI) is able to cause permanent
nano-sized hillocks on the surface of a CaF2 single crystal
[1]. The experimentally observed threshold of the projectiles
potential energy necessary for hillock formation could be
successfully linked to a solid-liquid phase transition (nanomelting)
[1 - 3]. Meanwhile a variety of materials has been
found, which are susceptible to nano-structuring by the
impact of slow HCI [3]. The nature, appearance and stability
of the created structures, however, depend heavily on the
properties of the target material and the involved interaction
processes (determined by the potential and kinetic energy of
the projectiles) [3]. Not in all cases nano-hillocks but nanocraters
or -holes are formed on a surface, like for KBr [4] or
PMMA [5].
In this contribution we present the first investigations on the
effect of individual slow highly charged ion bombardment
of freestanding carbon nano-membranes [6].
2. EXPERIMENT
The carbon nanomembranes (CNMs) are produced by crosslinking
of an aromatic self-assembled monolayer of
biphenyl units with low-energy electrons. The substrate is
then subsequently removed and the resulting nanosheet
(1 nm thickness) transferred onto a holey carbon TEM grid.
CNMs produced in such a way are irradiated by slow highly
charged Xeq+ ions of various charge states (20 􀀁 q 􀀁 40) and
kinetic energies (4 keV 􀀁 E 􀀁 180 keV). After irradiation
the CNMs are inspected by high resolution imaging
techniques, e.g. transmission electron microscopy (TEM),
secondary electron microscopy (SEM), atomic force
microscopy (AFM) and He-ion microscopy (HIM).
3. RESULTS
After irradiation by slow HCI we find nanoscopic holes (3 -
30 nm in diameter) at positions, where the sheet extends
over holes in the carbon film (fig. 1). The number density of
these nanopores corresponds well with the incident ion
fluence, indicating that about every HCI produces a nanohole
in the CNM. These holes have so far been imaged in
TEM, SEM as well as in AFM.
Figure 1: TEM image of 2 holes in a carbon nanomembrane
induced by impact of two Xe40+ ions (Ekin = 40 keV, Epot = 38.5
keV).
First evaluations of the size distribution of the created holes
indicate that the average diameter of a pore induced by a
given ion depends strongly on the potential energy of the
projectile ion, but is also influenced by the kinetic energy.
4. ACKNOWLEDGEMENTS
This work has been supported by the EU Project SPIRIT
under EC contract no. 227012. Support by ÖAW and by
FWF is acknowledged. R. R. is a recipient of a DOCfellowship
of the Austrian Academy of Sciences at the
Institute of Applied Physics of TU Wien.

Erstellt aus der Publikationsdatenbank der Technischen Universitšt Wien.