Energy Transfer and Photoluminescence Enhancement in WS_(2)/hBN/MoS_(2) Heterostructures  

WS_(2)/hBN/MoS_(2)异质结中的能量转移和光致发光增强

作　　者：CHEN Pengyao REN Bingyan ZHANG Chengyu LI Boyuan WANG Jiaxi ZHANG Kaixuan ZHAO Weijie 陈朋尧;任冰燕;张丞昱;李博远;王嘉熙;张凯旋;赵伟杰(东南大学物理学院,江苏南京211189;东南大学吴健雄学院,江苏南京211102;紫金山实验室,江苏南京211111)

机构地区：[1]School of Physics,Southeast University,Nanjing 211189,China [2]Chien-Shiung Wu College,Southeast University,Nanjing 211102,China [3]Purple Mountain Laboratories,Nanjing 211111,China

出　　处：《发光学报》2024年第12期2021-2029,共9页Chinese Journal of Luminescence

基　　金：江苏省基础研究计划自然科学基金——前沿引领技术基础研究专项(BK20222007)。

摘　　要：Two-dimensional(2D)transition metal dichalcogenides(TMDs)and their heterostructures(HSs)exhibit unique optical properties and show great promise for developing next-generation optoelectronics.However,the photo-luminescence(PL)quantum yield of monolayer(1L)TMDs is still quite low at room temperature,which severely lim-its their practical applications.Here we report a PL enhancement effect of 1L WS_(2) at room temperature when con-structing it into 1L-WS_(2)/hBN/1L-MoS_(2) vertical HSs.The PL enhancement factors(EFs)can be up to 4.2.By using transient absorption(TA)spectroscopy,we demonstrate that the PL enhancement effect is due to energy transfer from 1L MoS_(2) to 1L WS_(2).The energy transfer process occurs on a picosecond timescale and lasts more than one hundred picoseconds which indicates a prominent contribution from exciton-exciton annihilation.Furthermore,the PL en-hancement effect of 1L WS_(2) can be observed in 2L-MoS_(2)/hBN/1L-WS_(2) and 3L-MoS_(2)/hBN/1L-WS_(2) HSs.Our study provides a comprehensive understanding of the energy transfer process in the PL enhancement of 2D TMDs and a fea-sible way to optimize the performance of TMD-based optoelectronic devices.二维过渡金属二硫族化合物(TMDs)及其异质结具有独特的光学特性,因此在发展下一代光电器件方面具有广阔的应用前景。但是,在室温下单层(1L)过渡金属二硫族化合物的光致发光效率非常低,这严重阻碍了其在光电器件中的实际应用。本文报道了一种增强单层TMDs的光致发光效率的有效方法,即通过构建1L-WS_(2)/hBN/1L-MoS_(2)垂直异质结,能够大幅提升单层WS_(2)的光致发光效率,其增强因子最高可达4.2。利用瞬态吸收光谱,我们验证了该荧光增强效应是由1L MoS_(2)向1L WS_(2)的能量转移引起的。能量传递过程发生在皮秒时间尺度上,但其持续时间超过100 ps,这表明激子-激子湮灭对能量转移有重要影响。此外,在2L-MoS_(2)/hBN/1L-WS_(2)和3L-MoS_(2)/hBN/1L-WS_(2)异质结中,我们均能观察到单层WS_(2)的荧光增强效应。本研究为深入理解二维TMDs异质结中的能量转移机制打下了良好的基础,并为优化基于TMDs异质结的光电器件性能提供了可行方案。

关 键 词：transition metal dichalcogenide van der Waals heterostructures PHOTOLUMINESCENCE Förster resonance energy transfer exciton-exciton annihilation 

分 类 号：O482.31[理学—固体物理]