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 G. Pedersen, Frank H.L. Koppens*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

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 WSe2 p-n junction. We find that under static inplane 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.
Original languageEnglish
Article number1633
JournalNature Communications
Volume9
Issue number1
Number of pages7
ISSN2041-1723
DOIs
Publication statusPublished - 2018

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