Origins, Visions, Plans & Wave Reactors

MON, 04/25/2011 - 4:00PM TO 5:00PM
Spring 2011 Colloquium Series

Low-energy ion irradiation of semiconductor surfaces [1] opens an elegant and efficient route towards fabrication of large-scale arrays of uniform semiconductor nanostructures. Using power spectral density analysis of atomic force microscopy (AFM) images, the degree of pattern uniformity can be quantified as is demonstrated for ion- bombardment induced GaSb dot arrays [2]. Attempts to obtain similar pattern formation by ion-bombardment of clean silicon substrates fail [3], unless there is a supply of metal impurities [4].

Since the ion-bombardment induced nanostructure arrays cover the entire sample surface, they can be used as large-area nanopatterned templates for subsequent deposition of magnetic thin films. This will be illustrated for the shadow deposition of cobalt onto ion-bombardment induced GaSb dot patterns. It will further be demonstrated how pre-ion bombardment can influence the resulting growth mode of organic semiconductor films [6]. Finally, it is shown that friction force microscopy and atomic-force microscopy can be employed to study single impacts of highly charged ions.

[1] S. Facsko, et. al., Science 285 (1999) 1551;
[2] T. Bobek, et al., Phys. Rev. B 68 (2003) 085324.
[3] C. Hofer, et al., Nucl. Instrum. Meth. B 216 (2004) 178.
[4] C. Teichert, et al., Adv. Eng. Mat. 8 (2006) 1057-1065.
[5] C. Teichert, et al., J. Cond. Mat. Phys. 21 (2009) 224025.
[6] G. Hlawacek, et al., Science. 321 (2008) 108.

This research has been supported in the framework of the European Project NAMASOS (Nanomagnets by Self-Organisation, Grant No. STRP 505854-1) and by Austrian Science Fund within NFN “Organic Thin Films” project S9707.