<br>单层 TMDC 中经 TEM 处理的缺陷密度及其在 PL 和拉曼光谱中的基底依赖性特征,Nanotechnology

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单层 TMDC 中经 TEM 处理的缺陷密度及其在 PL 和拉曼光谱中的基底依赖性特征
Nanotechnology ( IF 2.9 ) Pub Date : 2024-08-07 , DOI: 10.1088/1361-6528/ad6875
Narine Moses Badlyan ₁ , Moritz Quincke _{2,

3} , Ute Kaiser _{2,

3} , Janina Maultzsch ₁

Affiliation

直接带隙过渡金属二硫属化物（TMDC）MoS ₂和WS ₂的光学性质很大程度上受其原子缺陷结构和基底相互作用的影响。在这项工作中，我们使用低电压色差和球差 (C _C /C _S ) 校正的高分辨率透射电子显微镜来同时创建 TMDC 中的硫族空位并对其进行成像。然而，由于所涉及的视场和样品平台截然不同，因此将使用透射电子显微镜 (TEM) 生成和分析的缺陷结构与光谱学关联起来通常会带来挑战。在这里，我们采用反向转移技术将电子辐照的单层 MoS ₂和 WS ₂从 TEM 网格转移到各种基材上以进行后续光学检查。在单独样品上以原子分辨率研究缺陷产生的动力学，这允许将导出的统计数据应用于其他样品上更大的辐照区域。光致发光（PL）中缺陷束缚激子峰的强度和缺陷诱导的激子峰的强度洛杉矶拉曼光谱中的 (M) 模式随着缺陷密度的增加而增加。通过光谱测定缺陷密度的最佳基底是用于 PL 的聚苯乙烯和用于拉曼光谱的 SiC 和 Si/SiO ₂ 。这些研究代表了仅使用光谱学来量化缺陷的重要一步，为光电器件的快速、可靠和自动化光学质量控制铺平了道路。

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TEM-processed defect densities in single-layer TMDCs and their substrate-dependent signature in PL and Raman spectroscopy

The optical properties of the direct-bandgap transition metal dichalcogenides (TMDCs) MoS₂ and WS₂ are heavily influenced by their atomic defect structure and substrate interaction. In this work we use low-voltage chromatic and spherical aberration (C_C/C_S)-corrected high-resolution transmission electron microscopy to simultaneously create and image chalcogen vacancies in TMDCs. However, correlating the defect structure, produced and analyzed using transmission electron microscopy (TEM), with optical spectroscopy often presents challenges because of very different fields of view and sample platforms involved. Here we employ a reverse transfer technique to transfer electron-irradiated single-layer MoS₂ and WS₂ from the TEM grid to various substrates for subsequent optical examination. The dynamics of defect creation are studied in atomic resolution on a separate sample, which allows to apply the derived statistics to larger irradiated areas on the other samples. The intensity of both the defect-bound exciton peak in photoluminescence (PL) and the defect-induced LA(M) mode in Raman spectra increase with defect density. The best substrates for defect-density determination by optical spectroscopy are polystyrene for PL and SiC and Si/SiO₂ for Raman spectroscopy. These investigations represent an important step towards the quantification of defects using solely optical spectroscopy, paving the way for fast, reliable, and automatable optical quality control of optoelectronic devices.

更新日期：2024-08-07

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