Ferromagnetic Properties of Fe-Doped Tungsten Diselenide Monolayers Toward Diluted Magnetic Semiconductors

When and Where

Dec 2, 2022
4:15pm - 4:30pm

Hynes, Level 2, Room 207

Presenter

Mengqi Fang

Siwei Chen

Kyungnam Kang

Arunabh Mukherjee

A. Nick Vamivakas

Eui-Hyeok Yang

Co-Author(s)

Mengqi Fang¹,Siwei Chen¹,Kyungnam Kang¹,Arunabh Mukherjee²,A. Nick Vamivakas²,Eui-Hyeok Yang¹

Stevens Institute of Technology¹,University of Rochester²

Abstract

Mengqi Fang¹,Siwei Chen¹,Kyungnam Kang¹,Arunabh Mukherjee²,A. Nick Vamivakas²,Eui-Hyeok Yang¹

Stevens Institute of Technology¹,University of Rochester²

Two-dimensional (2D) transition metal dichalcogenides (TMDs) possess interesting electronic, optical, and structural features, including a direct band gap in monolayers with a photoluminescence emission in the visible and near-infrared spectral range [1-2], which due to transition metal atoms fill non-bonded d-bands to a variety of levels [3]. With the superior 2D atomic thickness and tunable electronic band structure, TMDs, have become suitable candidates for studying high nonlinear optical susceptibilities, spin-orbit interactions, and novel valleytronics properties [4]. Doping is an efficient way to tune the properties of TMDs. These 2D TMD semiconductors doped with transition metal atoms (such as vanadium (V), Rhenium (Re), and iron (Fe)) link the properties of semiconductors and ferromagnets, creating new known as dilute magnetic semiconductors (DMS) [5]. These 2D DMS were synthesized via chemical vapor deposition (CVD), thereby opening the door toward utilizing novel modes of magneto-electronic and magneto-optical responses of 2D heterostructures [6-8]. Here we demonstrate an in situ substitutional doping of iron atoms into WSe2 monolayers via low-pressure chemical vapor deposition (LPCVD). Fe3O4 particles as iron sources were cast onto the SiO2/Si substrate, and a MoO3-deposited substrate contacted the source substrate face-to-face. The furnace was then heated to 850 °C and held for 15 mins. During the heating process, selenium (Se) is provided via vaporizing Se powder placed in crucibles outside the central furnace area as the furnace temperature rises to 640 °C. Argon (Ar) gas was flown to the furnace at 200 °C, and hydrogen (H2) gas was supplied at 660 °C. To verify the growth of monolayer Fe: WSe2 domains, we first characterized the samples via Raman/PL spectroscopy and atomic force microscopy (AFM), confirming that the grown materials are Fe-doped WSe2 monolayers. We plan to characterize the ferromagnetic domains of the grown materials using magnetic force microscopy (MFM) at our facility (new MFM equipment has been recently installed). Finally, the ferromagnetic nature of the grown Fe-doped WSe2 monolayers will be confirmed using spatially resolving nitrogen-vacancy (NV-) center magnetometry (this characterization has been routinely performed by the authors’ group [9]). Reference: [1] A. K. Geim et al., Science, 324 (5934). 1530–1534, 2009. [2] Q. Fu et al., Advanced Materials, 33 (6), 1907818, (2021). [3] M. Chhowalla et al., Nature Chemistry, 5 (4), 263–275, (2013). [4] R. Lv et al., Accounts of chemical research, 48 (1), 56–64, (2015). [5] Furdyna et al., Journal of Applied Physics, 61 (8), 3526-3531, (1987). [6] S. Tiwari et al., npj 2D Materials and Applications, 5 (1), 1–7, (2021). [7] S. J. Yun et al., Advanced Science, 7 (9), 1903076, (2020). [8] Z. Jiang et al., Nanoscale Horizons, 3 (3), 335–341, (2018). [9] Fu, S et al., Nature communications, 11 (1), 1-8, (2020).