Boosting quantum yields in two-dimensional semiconductors via proximal metal plates

Yongjun Lee, Johnathas D’arf Severo Forte, Andrey Chaves, Anshuman Kumar, Trang Thu Tran, Youngbum Kim, Shrawan Roy, Takashi Taniguchi, Kenji Watanabe, Alexey Chernikov, Joon I. Jang, Tony Low, Jeongyong Kim

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Monolayer transition metal dichalcogenides (1L-TMDs) have tremendous potential as atomically thin, direct bandgap semiconductors that can be used as convenient building blocks for quantum photonic devices. However, the short exciton lifetime due to the defect traps and the strong exciton-exciton interaction in TMDs has significantly limited the efficiency of exciton emission from this class of materials. Here, we show that exciton-exciton interaction in 1L-WS2 can be effectively screened using an ultra-flat Au film substrate separated by multilayers of hexagonal boron nitride. Under this geometry, induced dipolar exciton-exciton interaction becomes quadrupole-quadrupole interaction because of effective image dipoles formed within the metal. The suppressed exciton-exciton interaction leads to a significantly improved quantum yield by an order of magnitude, which is also accompanied by a reduction in the exciton-exciton annihilation (EEA) rate, as confirmed by time-resolved optical measurements. A theoretical model accounting for the screening of the dipole-dipole interaction is in a good agreement with the dependence of EEA on exciton densities. Our results suggest that fundamental EEA processes in the TMD can be engineered through proximal metallic screening, which represents a practical approach towards high-efficiency 2D light emitters.

Original languageEnglish (US)
Article number7095
JournalNature communications
Volume12
Issue number1
DOIs
StatePublished - Dec 2021
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the Samsung Research Funding & Incubation Center of Samsung Electronics, under project no. SRFC-MA1802-02. A.K. acknowledges funding support from the Department of Science and Technology (DST). A. Chaves and J.D.S.F. acknowledge financial support by the Brazilian Research Council (CNPq), through the PRONEX/FUNCAP and PQ programs. A. Chaves also acknowledges financial support by the Research Foundation - Flanders (FWO). A. Chernikov gratefully acknowledges financial support by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through SFB 1277 (Project-ID 314695032) project B05, Emmy-Noether Grant CH 1672/1 (Project-ID: 287022282), and the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter ct.qmat (EXC 2147, Project-ID: 390858490). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant Number JPMXP0112101001), JSPS KAKENHI (Grant Numbers 19H05790, 20H00354 and 21H05233) and A3 Foresight by JSPS.

Publisher Copyright:
© 2021, The Author(s).

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