Twisted-Angle-Dependent Optical Behaviors of Intralayer Excitons and Trions in WS2/WSe2 Heterostructure

• Published in: ACS photonics Vol. 6; no. 12; pp. 3082 - 3091
• Main Authors: Shi, Jia, Li, Yuanzheng, Zhang, Zhepeng, Feng, Weiqiang, Wang, Qi, Ren, Shuliang, Zhang, Jun, Du, Wenna, Wu, Xianxin, Sui, Xinyu, Mi, Yang, Wang, Rui, Sun, Yuanhui, Zhang, Lijun, Qiu, Xiaohui, Lu, Jiong, Shen, Chao, Zhang, Yanfeng, Zhang, Qing, Liu, Xinfeng
• Format: Journal Article
• Language: English
• Published: American Chemical Society 18.12.2019
• Subjects: WS2/WSe2 heterostructure; excitons; twisted angle; trions; carrier dynamics
• DOI: 10.1021/acsphotonics.9b00855
• ISSN: 2330-4022

Understanding the formation and recombination dynamics between excitons and trions is critical for evaluating and improving the performance of two-dimensional material-based optoelectronic devices. Herein, we have investigated the competitive luminescence processes of intralayer excitons and trions in WS2/WSe2 heterostructures with different (0°, 30°, and 60°) twisted angles. We observed the increased photoluminescence (PL) ratio of trions compared to excitons in heterostructures with twisted angles of 30° and 60°. For a twisted angle of 30°, the relatively large PL ratio of trions is caused by the high probability of trion formation than that of excitons, while for a twisted angle of 60°, the ultrafast formation time of trions is the main reason for the trion-dominant proportion in the PL spectrum. Moreover, the power law between the excitation laser and the PL emission intensity reflects how the many-body effect affects the competition luminescence of excitons and trions. Our present results provide further understanding of the optical behaviors of intralayer excitons and trions in different twisted angle heterostructures.