Moritz Will: A monolayer of hexagonal boron nitride on Ir(111) as a template for cluster growth

posted 27 Jun 2017, 07:23 by info admin
Moritz Will (1), Philipp Valerius (1), Charlotte Herbig (1), Vasile Caciuc (2), Nicolae Atodiresei (2) and Thomas Michely (1)

(1) II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
(2) Peter Grünberg Institut (PGI) and Institute for Advanced Simulation (IAS),
Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Chemical vapor deposition of borazine molecules on Ir(111) results in a well aligned monolayer of hexagonal boron nitride (h-BN) which forms an incommensurate (11.7 x 11.7) moiré on (10.7 x 10.7) substrate unit cells. The center of each unit cell provides a chemisorbed valley area, where h-BN is hybridized with the Ir substrate [1]. Through a scanning tunneling microscopy study we provide evidence that the valley regions are reactive and pin deposited atoms. In consequence, highly regular cluster arrays with a periodicity of 2.9 nm can be formed. For the case of Ir clusters, the size distribution is narrow. The average size can be tuned between a few to about 200 atoms for room temperature deposition. The thermal stability of the clusters is extraordinary, with a decay of the cluster lattice setting only at around 850 K, primarily through intercalation of the cluster material. Regularly positioned C clusters on h-BN are even observed after annealing to 1500 K. Compared to cluster arrays using graphene on Ir(111) as a template, the better order and the higher thermal stability make the arrays on h-BN/Ir(111) superior in terms of potential applications for nano-catalysis. We elucidated the cluster binding mechanism of Ir clusters to h-BN/Ir(111) with the help of density functional theory calculations.

[1] Farwick zum Hagen, Ferdinand H., et al. "Structure and Growth of Hexagonal Boron Nitride on Ir (111)." ACS nano 10.12 (2016): 11012-11026.

I am currently working as a PhD student in the group of Thomas Michely at the II. Physikalisches Institut in Cologne, where the interest mainly lies in the investigation of two-dimensional materials, ion-surface-interactions and molecular (magnetic) nanostructures by means of scanning tunnelling microscopy and spectroscopy. During my undergraduate, I studied pattern formation by ion irradiation on silicon. Now, the focus lies on self-assembled cluster lattices on two-dimensional materials and applications thereof.