Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 65: 2D Materials 2: Growth, Structure and Substrate Interaction
O 65.1: Vortrag
Donnerstag, 8. September 2022, 10:30–10:45, S052
Segregation-enhanced epitaxy of borophene on Ir(111) by thermal decomposition of borazine — •Karim Omambac1, Marko Kriegel1, Marin Petrovic1,2, Pantelis Bampoulis4, Christian Brand1, Pascal Dreher1, David Janoschka1, Ulrich Hagemann3, Nils Hartmann3, Philipp Valerius4, Thomas Michely4, Frank-J. Meyer zu Heringdorf1,3, and Michael horn-von Hoegen1 — 1Universität Duisburg-Essen, Germany — 2Institute of Physics, 10000 Zagreb, Croatia — 3Interdisciplinary Center for the Analytics on the Nanoscale, Germany — 4Universität zu Köln, Germany
While borophene is typically prepared by molecular beam epitaxy [1], we report here on an alternative way of synthesizing large single-phase borophene domains by segregation enhanced epitaxy. X-ray photoelectron spectroscopy shows that borazine dosing at 1100°C onto Ir(111) yields a boron-rich surface without traces of nitrogen. At high temperatures the borazine thermally decomposes, nitrogen desorbs, and boron diffuses into the substrate. Using time-of-flight secondary ion mass spectroscopy we show that during cooldown the sub-surface boron segregates back to the surface where it forms borophene. In this case electron diffraction reveals a (6x2) reconstructed borophene χ6-polymorph [1], and scanning tunneling spectroscopy suggests a Dirac-like behavior. Studying the kinetics of borophene formation in low energy electron microscopy shows elongated and extended borophene domains with exceptional structural order. [1] ACS Nano 13 (12), 14511-14518 (2019).