Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 51: Oxides and insulators: Epitaxy and growth
O 51.5: Vortrag
Mittwoch, 28. März 2012, 17:45–18:00, HE 101
Growth and characterization of hexagonal boron nitride on Cu(111) — •Sushobhan Joshi1, Willi Auwärter1, Felix Bischoff1, David Ecija1, Saranyan Vijayaraghavan1, Hermann Sachdev2, and Johannes V. Barth1 — 1Physik Department E20, Technische Universität München, James-Franck Str. 1, D-85748 Garching, Germany — 2Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128 Mainz, Germany
Monolayer systems as hexagonal boron nitride (h-BN) or graphene can be epitaxially grown on various metal supports and recently attract considerable interest. Here we present a scanning tunneling microscopy (STM) and spectroscopy (STS) study characterizing hexagonal boron nitride (sub)monolayers grown on a Cu(111) surface by thermal decomposition of a borazine precursor. While no h-BN related contrast is observed in topographic images recorded at low bias, Moire patterns emerge at a voltage of about 4 V. Independent on the preparation procedure, we observe the coexistence of such patterns exhibiting different periodicities and orientations. This evidences the formation of various h-BN domains on the surface and thus points to a weak interaction of the h-BN sheet with the underlying Cu(111) lattice. Electronically, the h-BN/Cu(111) system is characterized by an interface state emerging from the Cu(111) surface state. Additionally, ST spectra recorded in the field emission regime indicate a spatially modulated workfunction on h-BN that is reduced in comparison to bare Cu(111). Such local variations of the surface electronic structure influence the formation of molecular assemblies as outlined for the case of porphines.