Dissociation of two-dimensional excitons in monolayer WSe2

Mathieu Massicotte, Fabien Vialla, Peter Schmidt, Mark B. Lundeberg, Simone Latini, Sten Haastrup, Mark Danovich, Diana Davydovskaya, Kenji Watanabe, Takashi Taniguchi, Vladimir I. Fal'ko, Kristian Sommer Thygesen, Thomas Garm Pedersen, Frank H. L Koppens

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54 Citationer (Scopus)
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Two-dimensional (2D) semiconducting materials are promising building blocks for optoelectronic applications, many of which require efficient dissociation of excitons into free electrons and holes. However, the strongly bound excitons arising from the enhanced Coulomb interaction in these monolayers suppresses the creation of free carriers. Here, we identify the main exciton dissociation mechanism through time and spectrally resolved photocurrent measurements in a monolayer WSe 2 p-n junction. We find that under static in-plane electric field, excitons dissociate at a rate corresponding to the one predicted for tunnel ionization of 2D Wannier-Mott excitons. This study is essential for understanding the photoresponse of 2D semiconductors and offers design rules for the realization of efficient photodetectors, valley dependent optoelectronics, and novel quantum coherent phases.

TidsskriftNature Communications
Udgave nummer1
Antal sider7
StatusUdgivet - 24 apr. 2018

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