Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster Session I

HL 13.21: Poster

Monday, March 12, 2018, 17:30–19:30, Poster B

Spatially resolved photoluminescence of mono- and bilayer molybdenum ditelluride — •Matthias Kunz¹, Sophia Helmrich¹, Robert Schneider², Alexander W. Achtstein¹, Ashish Arora², Bastian Herzog¹, Steffen Michaelis de Vasconcellos², Mirco Kolarczik¹, Oliver Schöps¹, Rudolf Bratschitsch², Nina Owschimikow¹, and Ulrike Woggon¹ — ¹Institut für Optik und Atomare Physik, Technische Universität Berlin, Germany — ²Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Germany

We study the photoluminescence of a mechanically exfoliated molybdenum ditelluride (MoTe₂) flake in the spatial crossover region from monolayer (ML) to bilayer (BL) at low temperatures. To repeatedly address identical locations on the flake, we develop a camera-piezo feedback loop and confirm the reproducibility of the data obtained in different runs. In contrast to other transition metal dichalcogenides (TMD) materials, the MoTe₂ BL shows a strong luminescence comparable in intensity to the ML. The peak energy of the BL exciton is red-shifted by about 35 meV with respect to the ML, but displays a shift to larger energies at close distances to the ML/BL border. With edge effects thus influencing the peak positions, our results underline the importance of correct positioning of the excitation spot on TMD flakes.