Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: 2D Materials III: Electronic Structure (joint session O/TT)

O 44.7: Vortrag

Mittwoch, 20. März 2024, 12:00–12:15, MA 005

Strain-dependent electromechanical and optoelectronic properties of free-standing PtSe2 films — •Natalie Galfe, Stefan Heiserer, Maximilian Wagner, Michael Loibl, Silke Boche, Simon Schlosser, Oliver Hartwig, Tanja Stimpel-Lindner, Cormac Ó Coileáin, Kangho Lee, George de Coster, Paul Seifert, and Georg S. Duesberg — University of the Bundeswehr Munich

We report on the piezoresistive and optoelectronic properties of free-standing noble metal dichalcogenide PtSe₂ films under controlled strain. Bridges of polycrystalline PtSe₂ films with different geometries were fabricated directly on target substrates. The pre-structered platinum channels were selenized through thermally assisted conversion and the resulting PtSe₂ electrically contacted and underetched. The controlled strain of the bridges was induced by application of back-gate voltages. This makes them an excellent platform to study the impact of strain on transport and optoelectronic properties.

Increasing tensile strain shows a decrease in the electrical resistance, which is attributable to an enhancement of the density of states at the Fermi level. Raman analysis of the channel under increasing static strain displays a blue-shift of the Raman modes, which can be attributed to a decrease in effective film thickness which is supported by finite element simulations of the polycrystalline films. By applying AC gate voltages, the geometry-dependent eigenfrequencies of the bridges can be determined proving their expected mechanical oscillations. The results lead to a deeper understanding of this novel material class and serve as a platform for further applications.