The effects of substitutional Fe-doping on magnetism in MoS2and WS2monolayers

Kyungnam Kang; Shichen Fu; Kamran Shayan; Yoshimura Anthony; Siamak Dadras; Xiong Yuzan; Fujisawa Kazunori; Mauricio Terrones; Wei Zhang; Stefan Strauf; Vincent Meunier; A Nick Vamivakas; Eui-Hyeok Yang

doi:10.1088/1361-6528/abcd61

The effects of substitutional Fe-doping on magnetism in MoS₂and WS₂monolayers

Nanotechnology. 2020 Dec 10;32(9). doi: 10.1088/1361-6528/abcd61.

Authors

Kyungnam Kang¹, Shichen Fu¹, Kamran Shayan², Yoshimura Anthony³, Siamak Dadras², Xiong Yuzan^{4

5}, Fujisawa Kazunori⁶, Mauricio Terrones^{6

7}, Wei Zhang⁵, Stefan Strauf^{8

9}, Vincent Meunier³, A Nick Vamivakas^{2

10

11}, Eui-Hyeok Yang^{1

9}

Affiliations

¹ Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, United States of America.
² The Institute of Optics, University of Rochester, Rochester, NY 14627, United States of America.
³ Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, United States of America.
⁴ Department of Electrical and Computer Engineering, Oakland University, Rochester, MI 48309, United States of America.
⁵ Department of Physics, Oakland University, Rochester, MI 48309, United States of America.
⁶ Department of Physics and Center for 2-Dimensional and Layered Materials, Pennsylvania State University, University Park, PA 16802, United States of America.
⁷ Department of Chemistry and Materials Science & Engineering, Pennsylvania State University, University Park, PA 16802, United States of America.
⁸ Department of Physics, Stevens Institute of Technology, Hoboken, NJ 07030, United States of America.
⁹ Center for Quantum Science and Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, United States of America.
¹⁰ Department of Physics, University of Rochester, Rochester, NY 14627, United States of America.
¹¹ Center for Coherence and Quantum Optics, University of Rochester, Rochester, NY 14627, United States of America.

PMID: 33232946
DOI: 10.1088/1361-6528/abcd61

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 MoS₂and WS₂monolayers 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:MoS₂and Fe:WS₂show PL quenching and n-type doping, Fe dopants in WS₂monolayers are found to assume deep-level trap states, in contrast to the case of Fe:MoS₂, where the states are found to be shallow. Usingμm- and mm-precision local NV^-magnetometry and superconducting quantum interference device, we discover that, unlike MoS₂monolayers, WS₂monolayers do not show a magnetic phase transition to ferromagnetism upon Fe-doping. The absence of ferromagnetism in Fe:WS₂is corroborated using density functional theory calculations.

Keywords: chemical vapor deposition; dilute magnetic semiconductor; ferromagnetism; n-type doping; substitutional doping; trap states.