Single-layer tungsten disulfide (WS₂) is among the most widely investigated two-dimensional materials. Synthesizing it over large areas would enable the exploitation of its appealing optical and electronic properties in industrial applications. However, defects of different nature, concentration and distribution profoundly affect the optical as well as the electronic properties of this crystal. Controlling the defect density distribution can be an effective way to tailor the local dielectric environment and therefore the electronic properties of the system. In this work we investigate the defects in single-layer WS₂, grown in different shapes by liquid phase chemical vapor deposition, where the concentration of certain defect species can be controlled by the growth conditions. The properties of the material are surveyed by means of optical spectroscopy, photoelectron spectroscopy and Kelvin probe force microscopy. We determine the chemical nature of the defects and study their influence on the optical and electronic properties of WS₂. This work contributes to the understanding of the microscopic nature of the intrinsic defects in WS₂, helping the development of defect-based technologies which rely on the control and engineering of defects in dielectric 2D crystals.

中文翻译：

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多形状单层二硫化钨缺陷域的测定和研究

单层二硫化钨（WS2 _）是研究最广泛的二维材料之一。大面积合成它可以在工业应用中利用其有吸引力的光学和电子特性。然而，不同性质、浓度和分布的缺陷深刻地影响着这种晶体的光学和电子特性。控制缺陷密度分布是调整局部介电环境以及系统电子特性的有效方法。在这项工作中，我们研究了通过液相化学气相沉积以不同形状生长的单层WS ₂中的缺陷，其中某些缺陷物质的浓度可以通过生长条件来控制。通过光谱学、光电子能谱和开尔文探针力显微镜来研究材料的性能。我们确定了缺陷的化学性质，并研究了它们对 WS ₂光学和电子性能的影响。这项工作有助于理解 WS ₂中固有缺陷的微观性质，有助于开发基于缺陷的技术，这些技术依赖于介电二维晶体中缺陷的控制和工程。