Regensburg 2010 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 5: Nanoengineered Thin Films
DS 5.1: Vortrag
Montag, 22. März 2010, 15:45–16:00, H8
Artificial granularity of two-dimensional arrays of nanodots prepared by electron-beam-induced-deposition (EBID) — •Fabrizio Porrati1, Roland Sachser1, Mike Strauss2, Iryna Andrusenko3, Tatiana Gorelik3, Ute Kolb3, and Michael Huth1 — 1Physikalisches Institut, Goethe-Universität, Frankfurt am Main — 2MPI für Biophysik, Frankfurt am Main — 3Institut für Physikalische Chemie, Gutemberg-Universität, Mainz
We have prepared 2D arrays of metallic nanodots embedded in an insulating matrix by means of EBID using the W(CO)6 precursor. By varying the electron beam parameters, i.e. beam current and energy, and the array pitch we obtain granular media with tunable electrical properties. The analysis of the current-voltage characteristic suggests that the transport takes place by electron tunneling between the artificial grains. In order to understand the nature of the granularity and thus, the origin of the electron transport behaviour, we perform TEM and micro-Raman investigations. Independently of the deposition beam parameters, TEM measurements show that the dots are constituted by non-crystalline W-C clusters embedded in a non-crystalline carbonaceous matrix. Raman spectra show two peaks, around 690 cm−1 and 860 cm−1, associated to W-C stretching modes, supporting the TEM data. Furthermore, the so called G and D peaks, at about 1560 cm−1 1350 cm−1, associated to vibration modes in disordered and amorphous carbon, are also detected. The analysis of the position of the peaks and of their relative intensity suggests that the microstructure of the matrix is between nanocrystalline and amorphous.