Boron nitride nanomesh: Functionality from a corrugated monolayer
Berner, Simon1; Corso, Martina1; Brugger, Thomas1; Widmer, Roland1; Groening, Oliver1; Laskowski, Robert2; Blaha, Peter2; Schwarz, Karlheinz2; Goriachko, Andrii3; Over, Herbert3; Gsell, Stefan3; Schreck, Matthias3; Sachdev, Hermann3; Greber, Thomas1; Osterwalder, Juerg1
1Switzerland;
2Austria;
3Germany

The decomposition of borazine (HBNH)3 precursor molecules on the hot rhodium (111) surface leads to the spontaneous formation of a highly regular hexagonal structure with a periodicity of 3.2 nm and with the appearance of a mesh with pores of about 2 nm in diameter: the so-called nanomesh [1]. This nanomesh is identified as a single, complete monolayer [2,3]. The 2 nm sized pores are formed by regions where the layer binds strongly to the underlying metal, while the regular network of mesh wires represents regions where the layer is not bonded to the substrate, resulting in a corrugation of about 0.5Å in the layer [2]. The nanomesh exhibits a remarkable thermal stability and chemical inertness: it is robust against immersion in water and electrolyte solution [3]. Moreover, it shows the functionality of a regular array of trapping potentials as it is demonstrated by the stable and site selective adsorption of different kinds of planar molecules as observed in scanning tunneling microscopy and ultraviolet photoelectron spectroscopy. Depending on the size of the molecules and the molecular coverage, individual molecules or molecular assemblies are trapped in the pores. The trapping potential has been determined by thermal desorption spectroscopy and the implication of the size of the molecules on the binding energy is discussed.
In summary, the nanomesh paves the way for applications as a template for the growth of ordered nanostructures, based on methods that rely on ultrahigh vacuum deposition techniques as well as on deposition from aqueous solutions.
[1] M. Corso et al., Science 303 (2004) 217.
[2] R. Laskowski et al. Phys. Rev. Lett., in press (2007).
[3] S. Berner, M. Corso, et al., submitted (2007).
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