Observation of long-lived interlayer excitons in monolayer MoSe2–WSe2 heterostructures

By P. Rivera, J. Schaibley, Aaron M. Jones, J. Ross, Sanfeng Wu, G. Aivazian, P. Klement, K. Seyler, Genevieve Clark, N. Ghimire and 4 more. Nature Communications, 2014

1,503 citations recorded by the source corpus.

Van der Waals bound heterostructures constructed with two-dimensional materials, such as graphene, boron nitride and transition metal dichalcogenides, have sparked wide interest in device physics and technologies at the two-dimensional limit. One highly coveted heterostructure is that of differing monolayer transition metal dichalcogenides with type-II band alignment, with bound electrons and holes localized in individual monolayers, that is, interlayer excitons. Here, we report the observation of interlayer excitons in monolayer MoSe2–WSe2 heterostructures by photoluminescence and photoluminescence excitation spectroscopy. We find that their energy and luminescence intensity are highly tunable by an applied vertical gate voltage. Moreover, we measure an interlayer exciton lifetime of ~1.8 ns, an order of magnitude longer than intralayer excitons in monolayers. Our work demonstrates optical pumping of interlayer electric polarization, which may provoke further exploration of interlayer exciton condensation, as well as new applications in two-dimensional lasers, light-emitting diodes and photovoltaic devices. Monolayer transition metal dichalcogenide heterostructures with type II band alignment have generated wide interest in device physics at the two-dimensional limit. Here, Rivera et al. observe interlayer excitons in vertically stacked MoSe2–WSe2 heterostructures and demonstrate tunability of the energy and luminescence.

Subfields: Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/6f287cf806759b2d7d1d12ee8f3cf56cee4977d1

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In Materials Chemistry

1. K. Novoselov
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3. E. Malic
4. Thomas Mueller
5. W. Yao
6. Xiaodong Xu
7. Hongyi Yu
8. A. Mishchenko

Citations in the corpus

• 2D materials and van der Waals heterostructures (2016, background): “Combining materials with different work functions can lead to photoexcited electrons and holes accumulated in different layers, giving rise to indirect excitons [e.g., as has been observed for the pairs MoS2/WSe2 (86) and MoSe2/WSe2 (87) (Fig.”
• Momentum-space indirect interlayer excitons in transition-metal dichalcogenide van der Waals heterostructures (2018, background): “The ILE PL, which is the most prominent emission peak at room temperature, decreases relative to the MoS2 intralayer emission as the temperature decreases, in stark contrast to the behavior for ILE of the K − K type observed in WSe2-MoS2 heterobilayers, where the ILE PL yield monotonously increases ”