Séminaire - 06/12/2023 - Emmanuel A. Fodeke - Mechanical behaviour of 2D materials on strained substrates: experimental investigation on MoS2

Invitation : Sylvain Clair (Département PHANO, Equipe NANO).

Diffusion : IM2NP, CINaM, Irphe, Madirel, LP3, PIIM (via T. Angot), CPT (T. Martin), Fédération de Chimie (via S. Viel), CP2M

SEMINAIRE Mercredi 06 décembre 2023 à 14h30

Salle des séminaires de l'Im2np, campus de Saint-Jérôme, 1er étage Bâtiment Poincaré

Emmanuel A. FODEKE

Institut Pprime, UPR 3346, CNRS - University of Poitiers, France

Mechanical behaviour of 2D materials on strained substrates: experimental investigation on MoS₂

Due to its impressive mechanical, optical and electrical properties, molybdenum disulfide (MoS₂), among transition metals dichalcogenides (TMDCs), is a good candidate for applications in flexible electronics, optoelectronic devices and catalysis. Characterising its mechanical response is thus a key point to exploit its potential and that is the goal of this study.

Transferring MoS₂ films from the growth substrate to other substrates of interest is a major challenge. Existing procedures lead to the destruction of the growth substrate, sample degradation and/or presence of sacrificial coating residue on the free surface. Therefore, we developed a new transfer method which guarantees a quick, reliable, chemical and impurity-free transfer to desired substrates while preserving the morphology and quality of the film for various physical analyses and applications.

To understand their mechanical behaviour, 2D films of MoS₂ transferred to polyether-ether-ketone (PEEK) substrates were subjected to uniaxial compression. The surface in-situ evolution under increasing/decreasing strains was investigated by scanning probe microscopy. Straight-sided buckles are evidenced above a specific strain, lying perpendicularly to the (Ox) compression axis (Fig. 1). The results are presented and discussed in the framework of the elastic theory describing the buckling phenomenon. Experimental data show larger buckle morphologies due to interfacial sliding of the film over the substrate and at the interfaces of different layers of the film. The results also indicate that the sliding magnitude increases linearly with strain.