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O: Fachverband Oberflächenphysik
O 29: Poster: 2D Materials
O 29.2: Poster
Dienstag, 19. März 2024, 12:30–14:30, Poster A
h-BN in the Making: The Surface Chemistry of Borazine on Rh(111) — •Eva Marie Freiberger1, Fabian Düll1, Phiona Bachmann1, Johann Steinhauer1, Hans-Peter Steinrück1, and Christian Papp1,2 — 1FAU Erlangen-Nürnberg, Erlangen, Germany — 2FU Berlin, Berlin, Germany
The intriguing properties of two-dimensional materials (2DM) gave rise to a vivid research field. One of the most-studied representatives of this class is hexagonal boron nitride (h-BN). In ultra-high vacuum (UHV), h-BN can be grown on a metal support via chemical vapor deposition (CVD) using suitable precursors, such as ammonia borane or borazine. h-BN grown on a lattice-mismatched substrate undergoes a buckling, which is, in the case of Rh(111), referred to as nanomesh.
In this UHV study, we investigated the evolution of the h-BN nanomesh from borazine on Rh(111) using synchrotron radiation-based high-resolution X-ray photoelectron spectroscopy (XPS). The adsorption of borazine at 130 K was followed in situ, showing that borazine adsorbs mainly as an intact molecule. By studying borazine on Rh(111) with NEXAFS, we were able to identify a flat-lying adsorption geometry. For a better understanding regarding the formation of h-BN, the thermally-induced reaction of borazine on Rh(111) was investigated by temperature-programmed XPS. We find that borazine multilayers already desorb below 200 K. At 300 K, dehydrogenation of the remaining monolayer occurs, and boron nitride starts to grow in a disordered fashion. Above 600 K, the formation of the nanomesh sets in and, at about 1100 K, the conversion to h-BN is complete.
Keywords: borazine; h-BN; 2D materials; XPS; synchrotron radiation