Twisted-Angle-Dependent Optical Behaviors of Intralayer Excitons and Trions in WS2/WSe2 Heterostructure
Jia Shi, Yuanzheng Li, Zhepeng Zhang, Weiqiang Feng, Qi Wang, Shuliang Ren, Jun Zhang, Wenna Du, Xianxin Wu, Xinyu Sui, Yang Mi, Rui Wang, Yuanhui Sun, Lijun Zhang, Xiaohui Qiu, Jiong Lu, Chao Shen, Yanfeng Zhang, Qing Zhang, Xinfeng Liu
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.