[Zurück]

F. Aumayr:
"Nano-hillock formation due to impact of HCI on lamellar materials";
Vortrag: Selected oral contribution 23rd Intern. Conf. on Atomic Collisions in Solids (ICACS 23), Phalaborwa/South Africa; 20.08.2008; in: "Book of Abstracts 2008 23rd Intern. Conf. on Atomic Collisions in Solids (ICACS 23)", (2008), S. 69.

We have recently successfully demonstrated the possibility to produce well-defined
nano-hillocks by impact of slow highly charged ions (HCI) on CaF2 and other single
crystal surfaces [1-2]. In all cases where hillocks have been observed, nanostructure
formation is linked to a certain minimum potential energy carried into the surface
(potential energy threshold) [3]. Results have been analyzed on the basis of the
"inelastic thermal spike model" [4]. Simulation calculations performed along this line
indicate that the formation of hillocks is due to a local melting of the surface [1, 5].
We have now used highly charged Arq+ (11 < q < 16) and Xeq+ ions (13 q 30)
extracted from the ARIBE facility in Caen to irradiate lamellar materials like HOPG
(highly oriented pyrolytic graphite) and mica targets at kinetic energies of about 5 - 15
kV/q. Scanning tunneling microscopy analysis of the irradiated HOPG surfaces showed
hillock-like nanostructures, whose size corresponds very well with previous results by
other groups [3]. Surprisingly the nano-defects were also visible in atomic force
microscopy, however, we found clear evidence that the structures on HOPG are not of
topographical nature.
This work has been supported by the Austrian Science Foundation FWF (project
P17449). The experiments were performed at the distributed LEIF-Infrastructure
ARIBE at Caen, France, supported by Transnational Access granted by the European
Project ITS - LEIF (RII3#026015).
[1] A. S. El-Said, et al. NIM B 258 (2007) 167; A. S. El-Said, et al. NIM B 256 (2007)
346;
[2] A. S. El-Said, et al. Rad. Eff. Def. Solids 162 (2007) 467
[3] F. Aumayr, et al. NIM B (2008), doi:10.1016/j.nimb.2008.03.106
[4] M. Toulemonde, et al. Phys. Rev. B 46, (1992) 14362
[5] C. Lemell, et al., Sol. State Electr. 51 (2007) 1398