Berlin 2024 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 11: Poster I (joint session DS/MM/O)
DS 11.31: Poster
Mittwoch, 20. März 2024, 17:00–19:00, Poster B
The influence of PDMS residues on the mobility of molecules deposited onto Si/SiO2 wafers — •Erik von der Oelsnitz1,2, Tim Völzer1,2, Julian Schröer1, Tobias Korn1,2, and Stefan Lochbrunner1,2 — 1Institute of Physics, University of Rostock, Germany — 2Department "Life, Light & Matter", University of Rostock, Germany
The exfoliation and stamping of flakes of 2D materials onto a substrate is one of the most used methods for the preparation of transition metal dichalcogenide (TMDC) monolayers. However, it was found that during the transfer of the flake, impurities and in particular residues of the common stamp material polydimethyl siloxane (PDMS) are transferred to the substrate. This could have a major impact when analyzing TMDCs, especially in TMDC/molecule hybrid structures. In order to examine the effect of these impurities, dye molecules were evaporated onto a Si/SiO2 wafer and then measured in a fluorescence lifetime microscope (FLIM). Here, in a certain area, the dye coverage is removed by laser-induced photodegradation and the diffusion of the molecules into this depleted area is examined. Three wafers are compared, each representing a specific step of the preparation process. The FLIM measurements showed that the molecules on the bare wafer diffuse into the depleted area the fastest, while they take significantly longer on the samples that came into contact with PDMS. This shows that the surface properties of exfoliated 2D materials are significantly influenced by the contact with PDMS, which in turn has a major effect on the mobility and thus the dynamics of deposited molecules.