Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Poster Session I

DS 17.31: Poster

Dienstag, 13. März 2018, 18:15–20:15, Poster B

Epitaxially grown h-BN on Ir(111) under He ion irradiation: A route to form one atom thick membranes with an ordered array of nanometer sized holes — •Philipp Valerius, Carsten Speckmann, Alexander Herman, and Thomas Michely — II. physikalisches Institut, Universität zu Köln, 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 moiré with (11.7x11.7) h-BN on (10.7x10.7) Ir unit cells. The large h-BN super cell consists of a flat physisorbed mesa with small chemisorbed valleys which form a 2D hexagonal lattice with a pitch of about 3 nm. Here we demonstrate that single vacancies created in the h-BN monolayer on Ir(111) by low fluence 500 eV He ion irradiation at elevated temperatures order to vacancy clusters that are located in the initial valley regions. Consequently, a 2D antidot lattice of small holes with diameters of 0.5-1 nm is formed. The vacancy cluster formation is traced back to single vacancy mobility and preferential bonding of vacancy cluster edges to Ir(111) in the valley regions. Moreover, similar irradiation experiments for an h-BN monolayer on Pt(111) show that our observations represent a general principle of irradiation induced antidot lattice formation, rather than a unique case. Possible uses of such nanomesh membranes based on low energy irradiation are outlined.