We report simultaneous Raman scattering and photoluminescence (PL) mapping results to study the strain and doping effects of chemical treatment with bis(trifluoromethane) sulfonimide (TFSI) on the optical phonon, exciton, and trion characteristics of a vertically stacked monolayer–bilayer (1L–2L) MoS2 structure. Correlation analysis between the E ′ and A 1 ′ phonon energies revealed that tensile strain developed in the TFSI-treated MoS2 mainly by the filling of sulfur vacancies: 0.13% and 0.10% for 1L and 2L MoS2, respectively. In addition, TFSI-induced changes in the electron densities evaluated from the Raman correlation analysis were estimated to be − 0.38 × 10 13 cm − 2 and − 1.21 × 10 13 cm − 2 for 1L and 2L MoS2, respectively. The larger p-doping effect in 2L than in 1L MoS2 was attributed to a relatively higher defect density in the 2L region of the pristine MoS2, followed by a subsequent healing of the defects via chemical doping. The TFSI-induced change in electron density estimated from the PL result was in excellent agreement with the Raman correlation analysis. Furthermore, the Raman mapping and PL histogram analyses showed that structural defects in MoS2 could be effectively healed by chemical treatment.

中文翻译：

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化学处理对垂直堆叠单层-双层 MoS2 应变和电荷掺杂的影响

我们报告了同步拉曼散射和光致发光 (PL) 映射结果，以研究用双（三氟甲烷）磺酰亚胺（TFSI）进行化学处理对垂直堆叠单层-双层（1L）的光学声子、激子和三重子特性的应变和掺杂效应–2L) 二硫化钼结构。E ' 和 A 1 ' 声子能量之间的相关性分析表明，在 TFSI 处理的 MoS2 中主要通过填充硫空位产生拉伸应变：1L 和 2L MoS2 分别为 0.13% 和 0.10%。此外，对于 1L 和 2L MoS2，由拉曼相关分析评估的 TFSI 引起的电子密度变化估计分别为 - 0.38 × 10 13 cm - 2 和 - 1.21 × 10 13 cm - 2 。2L 中比 1L MoS2 更大的 p 掺杂效应归因于原始 MoS2 的 2L 区域中相对较高的缺陷密度，随后通过化学掺杂修复缺陷。从 PL 结果估计的 TFSI 引起的电子密度变化与拉曼相关分析非常一致。此外，拉曼映射和 PL 直方图分析表明，MoS2 中的结构缺陷可以通过化学处理得到有效修复。