The effects of substitutional Fe-doping on magnetism in MoS <sub>2</sub> and WS <sub>2</sub> monolayers
Kyungnam Kang, Shichen Fu, Kamran Shayan, Anthony Yoshimura, Siamak Dadras, Yuzan Xiong, Kazunori Fujisawa, Mauricio Terrones, Wei Zhang, Stefan Strauf, Vincent Meunier, A. Nick Vamivakas, Eui‐Hyeok Yang
Abstract
Abstract Doping of two-dimensional (2D) semiconductors has been intensively studied toward modulating their electrical, optical, and magnetic properties. While ferromagnetic 2D semiconductors hold promise for future spintronics and valleytronics, the origin of ferromagnetism in 2D materials remains unclear. Here, we show that substitutional Fe-doping of MoS 2 and WS 2 monolayers induce different magnetic properties. The Fe-doped monolayers are directly synthesized via chemical vapor deposition. In both cases, Fe substitutional doping is successfully achieved, as confirmed using scanning transmission electron microscopy. While both Fe:MoS 2 and Fe:WS 2 show PL quenching and n-type doping, Fe dopants in WS 2 monolayers are found to assume deep-level trap states, in contrast to the case of Fe:MoS 2 , where the states are found to be shallow. Using μ m- and mm-precision local NV − magnetometry and superconducting quantum interference device, we discover that, unlike MoS 2 monolayers, WS 2 monolayers do not show a magnetic phase transition to ferromagnetism upon Fe-doping. The absence of ferromagnetism in Fe:WS 2 is corroborated using density functional theory calculations.