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O: Fachverband Oberflächenphysik

O 24: Poster: Ion Beam Interaction with Surfaces and Interfaces

O 24.5: Poster

Monday, March 27, 2023, 18:00–20:00, P2/EG

Ion induced defects in two-dimensional tungsten diselenide boron nitride heterostructure — •Leon Daniel, Stephan Sleziona, Lucia Skopinski, Anke Hierzenberger, Jennifer Schmeink, and Marika Schleberger — Universität Duisburg-Essen, Germany

Monolayer transition metal dichalcogenides (TMDCs) like tungsten diselenide (WSe₂) are highly interesting materials for optoelectronic and valleytronic applications. We used Xe^q+ ions with Ekin=180 keV to deliberately introduce defects into the WSe₂ lattice and compared its optoelectronic properties before and after irradiation with photoluminescence spectroscopy. Encapsulation in hexagonal boron nitride (hBN) isolates the WSe₂ from environmental influences like adsorbates and detrimental interactions with the widely used Si/SiO₂ substrates. We find differences in the photoluminescence response for encapsulated and non-encapsulated WSe₂, which can be explained by the encapsulation preventing saturation of the created vacancies by adsorbates. In particular, there are various localized excitonic states in our different sample systems, and we explain this observation with differing ion interactions with encapsulated and non-encapsulated WSe₂. Furthermore, we observe overall highly increased exciton lifetimes after the irradiation, likely caused by the longer lifetime of the localized excitons.