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arXiv · 2603.00641

Origin of anomalous p-type conductivity in monolayer Fe-doped MoS2

Xiangning Quan·Xiaoqiu Yuan·Junwei Zhang·Xuebing Peng·Helin Mei·Cheng Yan·Hong Zhang·Hongli Li·Daqiang Gao·Yongjian Wang·Mingsu Si·Lili Zhang·Anmin Zhang·Zongyuan Zhang·Lei Shan·Yong Peng
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Abstract

Substitutional doping effectively modulates carrier polarity of semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDs) like MoS2. Although Fe doping typically induces n-type conductivity in monolayer MoS2, anomalous p-type behavior has also been experimentally reported, the origin of which remains unresolved. Here, we prove that this anomalous p-type conductivity originates from defect associates formed through interactions between Fe dopants and S atoms, which consists of three Fe substituting Mo (FeMo) point defects arranged into an equilateral triangle with a central S atom, denoted as 3FeMo-S associate. Its p-type effect is directly verified through scanning tunneling microscopy/scanning tunneling spectroscopy (STM/STS) measurement, in sharp contrast to the n-type behavior induced by isolated FeMo point defects, and the conclusion is further supported by electrical transport measurements and first-principles calculations. Similar 3FeW-S associates and their p-type doping effect are also identified in monolayer Fe-doped WS2. This work resolves a longstanding controversy and highlights the critical role of defect associates in modulating properties of 2D TMDs.

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Xiangning Quan, Xiaoqiu Yuan, Junwei Zhang, Xuebing Peng, Helin Mei, Cheng Yan, Hong Zhang, Hongli Li, Daqiang Gao, Yongjian Wang, Mingsu Si, Lili Zhang, Anmin Zhang, Zongyuan Zhang, Lei Shan, Yong Peng. 2026-02-28. Origin of anomalous p-type conductivity in monolayer Fe-doped MoS2. https://arxiv.org/abs/2603.00641

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