Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 28: 2D materials: Chalcogenides I (joint session HL/DS)

HL 28.14: Talk

Wednesday, March 14, 2018, 13:00–13:15, A 151

The Influence of the environment on monolayer tungsten diselenide photoluminescence — •Lorenz Maximilian Schneider¹, Sina Lippert¹, Jan Kuhnert¹, Obafunso Ajayi², Dylan Renaud¹, Young Duck Kim^2,3, Wolfram Heimbrodt¹, James C. Hone², and Arash Rahimi-Iman¹ — ¹Department of Physics and Material Sciences Center, Philipps-Universität Marburg, 35032 Marburg , Germany — ²Department of Mechanical Engineering, Columbia University, 10027 New York, USA — ³Department of Physics and Center for Humanities and Sciences, Kyung Hee University, 02447 Seoul, Republic of Korea

In recent years, two-dimensional (2D) semiconductors have drawn a lot of attention due to their special properties. Since transition metal dichalgogenides (TMDs) are a potential candidate for opto-electronic applications in the visible range, they are of major interest and subject of many studies. Recent investigations have shown that encapsulating monolayers with hBN can improve signal quality greatly compared to flakes grown or exfoliated on common substrates. Here, we present a systematic study of the effects, that such encapsulation of monolayers with mainly hBN can have on the 2D material’s optical properties using WSe₂. Besides the already known narrowing of the PL-linewidth, remarkable differences are found in the time evolution. hBN supported and encapsulated samples show a significantly stronger exciton-exciton annihilation as the reference samples on bare substrate. Furthermore, we show that this effect is also obtained if the heterostructure consists of two TMDs.