Abstract

Control of excitons in transition metal dichalcogenides (TMDCs) and their heterostructures is fundamentally interesting for tailoring light-matter interactions and exploring their potential applications in high-efficiency optoelectronic and nonlinear photonic devices. While both intra- and interlayer excitons in TMDCs have been heavily studied, their behavior in the quantum tunneling regime, in which the TMDC or its heterostructure is optically excited and concurrently serves as a tunnel junction barrier, remains unexplored. Here, using the degree of freedom of a metallic probe in an atomic force microscope, we investigated both intralayer and interlayer excitons dynamics in TMDC heterobilayers via locally controlled junction current in a finely tuned sub-nanometer tip-sample cavity. Our tip-enhanced photoluminescence measurements reveal a significantly different exciton-quantum plasmon coupling for intralayer and interlayer excitons due to different orientation of the dipoles of the respective e-h pairs. Using a steady-state rate equation fit, we extracted field gradients, radiative and nonradiative relaxation rates for excitons in the quantum tunneling regime with and without junction current. Our results show that tip-induced radiative (nonradiative) relaxation of intralayer (interlayer) excitons becomes dominant in the quantum tunneling regime due to the Purcell effect. These findings have important implications for near-field probing of excitonic materials in the strong-coupling regime.

Details

Title
Tailoring exciton dynamics in TMDC heterobilayers in the ultranarrow gap-plasmon regime
Author
Rahaman, Mahfujur 1   VIAFID ORCID Logo  ; Kim, Gwangwoo 2   VIAFID ORCID Logo  ; Ma, Kyung Yeol 3   VIAFID ORCID Logo  ; Song, Seunguk 1   VIAFID ORCID Logo  ; Shin, Hyeon Suk 3   VIAFID ORCID Logo  ; Jariwala, Deep 1   VIAFID ORCID Logo 

 University of Pennsylvania, Department of Electrical and Systems Engineering, Philadelphia, USA (GRID:grid.25879.31) (ISNI:0000 0004 1936 8972) 
 University of Pennsylvania, Department of Electrical and Systems Engineering, Philadelphia, USA (GRID:grid.25879.31) (ISNI:0000 0004 1936 8972); Chungbuk National University, Department of Engineering Chemistry, Chungbuk, Republic of Korea (GRID:grid.254229.a) (ISNI:0000 0000 9611 0917) 
 Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Department of Chemistry, Ulsan, Republic of Korea (GRID:grid.42687.3f) (ISNI:0000 0004 0381 814X) 
Pages
66
Publication year
2023
Publication date
2023
Publisher
Nature Publishing Group
e-ISSN
23977132
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2863647954
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.