Enhancement of Exciton Emission from Multilayer MoS2 at High Temperatures: Intervalley Transfer versus interlayer Decoupling
Enhancement of Exciton Emission from Multilayer MoS2 at High Temperatures: Intervalley Transfer versus interlayer Decoupling
复制标题
高温下多层 MoS2 激子发射的增强：谷间传输与层间解耦
DOI：
10.1002/smll.201700157
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发表时间：
2017-05-03
期刊：
影响因子：
13.3
通讯作者：
Liu, Yichun
中科院分区：
文献类型：
--
作者：
Li, Yuanzheng;Xu, Haiyang;Liu, Yichun
深入了解间接带隙多层膜MoS 2的载流子动力学特性，对进一步提高其发光效率具有重要意义。本文报道了多层MoS 2的反常发光行为，其激子发射在高温下显著增强。温度依赖的拉曼研究和电子结构计算表明，这种实验观察不能完全解释一个共同的机制。热膨胀引起的层间解耦。相反，提出了一个新的模型，涉及谷间转移的热激活载流子从A/F点到K点的理解多层二硫化钼的高温发光增强。稳态和瞬态荧光测量表明，激子发射的寿命和强度相对于增加温度而增加。这两个实验证据，以及一个计算的载体人口，提供了强有力的支持所提出的模型。
It is very important to obtain a deeper understand of the carrier dynamics for indirect-bandgap multilayer MoS2 and to make further improvements to the luminescence efficiency. Herein, an anomalous luminescence behavior of multilayer MoS2 is reported, and its exciton emission is significantly enhanced at high temperatures. Temperature-dependent Raman studies and electronic structure calculations reveal that this experimental observation cannot be fully explained by a common mechanism. of thermal-expansion-induced interlayer decoupling. Instead, a new model involving the intervalley transfer of thermally activated carriers from A/F point to K point is proposed to understand the high-temperature luminescence enhancement of multilayer MoS2. Steady-state and transient-state fluorescence measurements show that both the lifetime and intensity of the exciton emission increase relatively to increasing temperature. These two experimental evidences, as well as a calculation of carrier population, provide strong support for the proposed model.