Controlled contacting of single-walled carbon nanotubes

•Daniel Secker1, Ralph Krupke1, Heiko B. Weber1 und Hilbert v. Löhneysen2,3
2Forschungszentrum Karlsruhe, Institut für Festkörperphysik, PO-Box 3640, D-76021 Karlsruhe
3Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe
1Forschungszentrum Karlsruhe, Institut für Nanotechnologie, PO-Box 3640, D-76021 Karlsruhe

We present a method to encapsulate the ends of single-walled carbon nanotubes (SWNT) in metallic leads. For this purpose we employed an inorganic shadow mask of Si3N4 patterned by e-beam lithography on a PMMA/Si3N4/SiO2/Si substrate [1]. The SWNTs are deposited between the contacts after a first evaporation step by applying an ac electric field making use of the dielectrophoretic force [2]. A second evaporation step encapsulates the ends of the SWNTs by the metallic leads. Therefore in contrast to marker-assisted e-beam lithography any exposure of the SWNTs to organic substances like PMMA is avoided. We present low-temperature electrical transport measurements with samples thus prepared.

[1] T. Hoss et al., Microel. Engin. 46 (1999) 149-152

[2] R. Krupke et al., Appl. Phys. A 76 (2003) 397-400