Tailoring exciton dynamics in TMDC heterobilayers in the ultranarrow gap-plasmon regime
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 11, 2023
- Source ID
- 10.1038/s41699-023-00428-7
Entities
People
- Deep Jariwala
- Gwangwoo Kim
- Hyeon Suk Shin
- Kyung Yeol
- Mahfujur Rahaman
- Seunguk Song
Organizations
- Air Force Office of Scientific Research
- German Research Foundation
- National Research Foundation of Korea
- National Science Foundation