Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 80: 2D Materials Beyond Graphene: TMDCs, Silicene and Relatives (organized by O)

TT 80.8: Talk

Wednesday, March 18, 2015, 17:00–17:15, MA 005

Newly observed first-order resonant Raman modes in few-layer molybdenum disulfide — •Nils Scheuschner, Roland Gillen, Matthias Staiger, and Janina Maultzsch — Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin

We show measurements of two newly observed first-order Raman modes in few-layer MoS₂ with phonon energies of 286 cm⁻¹ and 471 cm⁻¹. These modes are strongly resonant and appear only when using excitation energies above ≈ 2.4 eV. At 2.7 eV, their intensity is comparable to the second-order Raman modes; their absence thus provides an easy and accurate method to identify single-layer MoS₂. At UV excitation, the intensity of the new modes is even larger than the typically examined A′₁/A_1g and E′/E_g modes. We provide a systematic analysis of the phonon modes, their symmetries, and their frequencies in few-layer materials, including the newly observed modes.