Interlayer donor-acceptor pair excitons in MoSe2/WSe2 moiré heterobilayer

Hongbing Cai; Abdullah Rasmita; Qinghai Tan; Jia-Min Lai; Ruihua He; Xiangbin Cai; Yan Zhao; Disheng Chen; Naizhou Wang; Zhao Mu; Zumeng Huang; Zhaowei Zhang; John J H Eng; Yuanda Liu; Yongzhi She; Nan Pan; Yansong Miao; Xiaoping Wang; Xiaogang Liu; Jun Zhang; Weibo Gao

doi:10.1038/s41467-023-41330-6

Interlayer donor-acceptor pair excitons in MoSe₂/WSe₂ moiré heterobilayer

Nat Commun. 2023 Sep 18;14(1):5766. doi: 10.1038/s41467-023-41330-6.

Authors

Hongbing Cai^{1

2}, Abdullah Rasmita¹, Qinghai Tan¹, Jia-Min Lai^{3

4}, Ruihua He⁵, Xiangbin Cai¹, Yan Zhao¹, Disheng Chen^{1

2}, Naizhou Wang¹, Zhao Mu¹, Zumeng Huang¹, Zhaowei Zhang¹, John J H Eng^{1

6}, Yuanda Liu^{1

2}, Yongzhi She⁷, Nan Pan⁷, Yansong Miao⁵, Xiaoping Wang⁷, Xiaogang Liu⁸, Jun Zhang⁹, Weibo Gao^{10

11

12}

Affiliations

¹ Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
² The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, 637371, Singapore.
³ State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China.
⁴ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
⁵ School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
⁶ Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore.
⁷ Department of Physics, University of Science and Technology of China, Hefei Anhui, 230026, China.
⁸ Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore.
⁹ State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China. zhangjwill@semi.ac.cn.
¹⁰ Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore. wbgao@ntu.edu.sg.
¹¹ The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, 637371, Singapore. wbgao@ntu.edu.sg.
¹² Centre for Quantum Technologies, National University of Singapore, Singapore, Singapore. wbgao@ntu.edu.sg.

Abstract

Localized interlayer excitons (LIXs) in two-dimensional moiré superlattices exhibit sharp and dense emission peaks, making them promising as highly tunable single-photon sources. However, the fundamental nature of these LIXs is still elusive. Here, we show the donor-acceptor pair (DAP) mechanism as one of the origins of these excitonic peaks. Numerical simulation results of the DAP model agree with the experimental photoluminescence spectra of LIX in the moiré MoSe₂/WSe₂ heterobilayer. In particular, we find that the emission energy-lifetime correlation and the nonmonotonic power dependence of the lifetime agree well with the DAP IX model. Our results provide insight into the physical mechanism of LIX formation in moiré heterostructures and pave new directions for engineering interlayer exciton properties in moiré superlattices.