SurfaceScience21 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 4: Mini-Symposium: Free-standing functional molecular 2D materials I

O 4.3: Vortrag

Montag, 1. März 2021, 11:15–11:30, R2

Atomic-scale carving of nanopores into a van-der-Waals heterostructure with slow highly charged ions — Janine Schwestka¹, Heena Inani², Mukesh Tripathi², Anna Niggas¹, Niall McEvoy³, Florian Libisch⁴, Friedrich Aumayr¹, Jani Kotakoski², and •Richard Wilhelm¹ — ¹TU Wien, Institute of Applied Physics — ²University Vienna, Faculty of Physics — ³Trinity College Dublin, AMBER School of Chemistry — ⁴TU Wien, Institute for Theoretical Physics

Tailoring the mechanical, electronic and chemical properties of functional 2D materials post-growth demands methods with highest surface sensitivity. Especially in van-der-Waals (vdW) heterostructures a method which only modifies a particular layer in the layer stack is highly beneficial. Here we report on nanoscale perforation of a MoS₂ layer on-top of a single layer of graphene by irradiation with individual slow highly charged ions. While we can perforate the MoS₂ layer with a high efficiency, the graphene stays intact. Even more so, when changing the layer order, the graphene facing the ion beam shields the MoS₂ from damage and the entire vdW heterostructure remains intact. While this monolayer sensitivity is based on different susceptibilities of metals and semi-conductors to highly charged ion induced potential sputtering, up to three layers of MoS₂ on-top of graphene also show perforation only in the topmost 1-2 layers. Hence, even a susceptible material can be perforated with monolayer precision. The mechanism of extreme surface sensitive energy deposition is discussed.