Berlin 2024 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 54: 2D Materials IV: Graphene (joint session O/TT)

TT 54.1: Talk

Wednesday, March 20, 2024, 15:00–15:15, MA 005

Ultra-large polymer-free suspended graphene films — •Lukas Kalkhoff, Sebastian Matschy, Ann-Sophie Meyer, Leon Lasnig, Nele Junker, Lars Breuer, and Marika Schleberger — Universität Duisburg-Essen, Fakultät für Physik, Germany

The quest to preserve graphene’s unique characteristics has intensified the demand for advanced preparation methods. The production of large area graphene films has been constrained by the necessity of a polymer film, like PMMA, during the transfer process, leading to unavoidable contaminations. In this talk, we show our approach to fabricate triple-layer graphene films, without the use of polymers, freely suspended across circular holes with diameters of 100-300 micrometers. This technique achieves a high yield and also ensures remarkable uniformity of the electronic properties of graphene, both across and within individual holes [1].

Using confocal Raman and THz spectroscopy we can confirm that the structural and electronic properties of these triple-layer films are akin to monolayer graphene. This discovery has significant implications, particularly in their application as ion-electron converters in time-of-flight mass spectrometry and similar fields. Remarkably, these graphene films are two orders of magnitude thinner than conventional carbon foils used in such experiments, yet they maintain robustness and a high electron yield, as proven under picosecond ion bombardment. This marks a critical step toward replacing existing carbon films or polymer-based graphene with cleaner, more precisely defined graphene films. [1] L. Kalkhoff et al., 2023, arXiv:2311.08137

Keywords: suspended graphene; free-standing; Raman; ion-solid-interaction; sub-nanosecond