Exciton–phonon interactions strongly affect photocarrier dynamics in two-dimensional materials. Here we report on resonant Raman experiments based on a graded composition W xMo1– xS2 alloy with tunable exciton energy without changing the energy of excitation laser. The intensities of the four most pronounced Raman features in the alloy are dramatically enhanced due to the resonance derived from the energy of B exciton shifting to the vicinity of the energy of excitation laser with an increase in W composition x. Specifically, through the resonance peak shift, absorption spectra and PL emission spectra under different excitation power, we conclude the resonance Raman is related to the exciton emission process. Our study extends the resonant Raman study of two-dimensional materials, which is expected to obtain deeper understanding of the excitonic effects in two-dimensional semiconductor materials.

中文翻译：

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具有可调谐激子的梯度成分 WxMo1–xS2 合金的共振拉曼散射

激子-声子相互作用强烈影响二维材料中的光载流子动力学。在这里，我们报告了基于分级成分 W 的共振拉曼实验X莫1–X小号2个具有可调谐激子能量的合金，无需改变激发激光的能量。由于 B 激子的能量随着 W 成分 x 的增加而转移到激发激光能量附近的共振，合金中四个最显着的拉曼特征的强度显着增强。具体来说，通过不同激发功率下的共振峰移、吸收光谱和PL发射光谱，我们得出共振拉曼与激子发射过程有关。我们的研究扩展了二维材料的共振拉曼研究，有望更深入地了解二维半导体材料中的激子效应。