Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 20: 2D materials: Chalcogenides I (joint session HL/DS)

DS 20.3: Talk

Wednesday, March 14, 2018, 10:00–10:15, A 151

Continually tuning the band gap of monolayer MoS₂ via mechanical strain — •Mohammad Bahmani¹, Mahdi Faghihnasiri², and Thomas Frauenheim¹ — ¹BCCMS, Physics Department, Bremen University, Bremen, Germany — ²Physics Department, Shahrood University of Technology, Shahrood, Iran

The idea of tuning material’s properties in a controllable and continuous manner by applying external mechanical field, is really appealing to researchers, particularly working on flexible devices. Several straining techniques have been employed, like bending of a flexible substrate, using of a piezoelectric substrate, controllably wrinkling, growing on a flexible substrate, and using the tip of an atomic force microscope. Since the discovery and synthesizing of semiconducting two-dimensional (2D) materials, studies have shown their high resilience to mechanical deformations in comparison to the conventional 3D semiconductors. On the other hand, electronic structure of the 2D materials, such as transition metal dichalcogenides (TMDCs), is proven to be very sensitive to structural deformations. In particular, monolayer of MoS₂ undergoes a direct-indirect band gap at around 1.5 percent compression and tensile strain. In addition, a semiconducting-metalic transition happens at more than 10 percent stretches. Therefore, we study the tunability of the electronic structure of monolayer MoS₂ under 5 distinguished mechanical strain.