Evolution of photoluminescence and Raman spectra in laterally gradient composition Mo1-xWxS2 alloys.

作者：Kangchen Deng, Chenxu Liu, Yutao Mo, Xiance Zheng, Jiahao Liao, Zijun Tang, Qiang Shu, Feng Zheng, Qiubao Lin, Ke Yang, Ming Yang, Shuqiong Lan, Wangying Xu, Huili Zhu, Changjie Zhou · 发表于：Journal of Chemical Physics · 年份：2026 · DOI：10.1063/5.0326798 · 被引用次数：1 · 研究领域：Medicine

Alloying two-dimensional semiconductors holds great promise to tailor electronic and optical properties for device applications. In this study, we report the synthesis of monolayer Mo1-xWxS2 alloys with a laterally gradient composition using an improved one-step chemical vapor deposition method. With increasing W composition, the intensity of exciton peak A exhibits a slow increase followed by a near-exponential enhancement, resulting in a significantly enhanced photoluminescence efficiency and a nonlinear blueshift of the peak. First-principles calculations reveal that this nonlinear blueshift is due to the predominant regulation of the conduction band by the Mo atom over a broad composition range. Furthermore, the asymmetry evolution within the conduction band can be attributed to the Mo-dz2 and W-dz2 orbital hybridizations in Mo1-xWxS2 alloys. At high W composition, the Raman spectra exhibit four peaks. The newly emerged A1g-mixed peak originates from the splitting of A1g peak in monolayer MoS2, corresponding to other out-of-plane vibrational modes of S atoms induced by W atoms. Furthermore, the evolution of Raman spectra is driven by lattice distortions and alterations in atomic vibrational modes. This work unravels the mechanism of composition-gradient-tuned electronic and optical properties of 2D Mo1-xWxS2 alloys, which could facilitate the development of next-generation electronic and optoelectronic devices.