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Bretscher H, Li Z, Xiao J, Qiu DY, Refaely-Abramson S, Alexander-Webber JA, Tanoh A, Fan Y, Delport G, Williams CA, Stranks SD, Hofmann S, Neaton JB, Louie SG, Rao A. Rational Passivation of Sulfur Vacancy Defects in Two-Dimensional Transition Metal Dichalcogenides. ACS Nano 2021; 15:8780-8789. [PMID: 33983711 PMCID: PMC8158852 DOI: 10.1021/acsnano.1c01220] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/07/2021] [Indexed: 06/01/2023]
Abstract
Structural defects vary the optoelectronic properties of monolayer transition metal dichalcogenides, leading to concerted efforts to control defect type and density via materials growth or postgrowth passivation. Here, we explore a simple chemical treatment that allows on-off switching of low-lying, defect-localized exciton states, leading to tunable emission properties. Using steady-state and ultrafast optical spectroscopy, supported by ab initio calculations, we show that passivation of sulfur vacancy defects, which act as exciton traps in monolayer MoS2 and WS2, allows for controllable and improved mobilities and an increase in photoluminescence up to 275-fold, more than twice the value achieved by other chemical treatments. Our findings suggest a route for simple and rational defect engineering strategies for tunable and switchable electronic and excitonic properties through passivation.
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Affiliation(s)
| | - Zhaojun Li
- University
of Cambridge, Cambridge, CB2 1TN, U.K.
- Uppsala
University, Uppsala, 751 20, Sweden
| | - James Xiao
- University
of Cambridge, Cambridge, CB2 1TN, U.K.
| | - Diana Yuan Qiu
- Yale
University, New Haven, Connecticut 06520, United States
| | | | | | - Arelo Tanoh
- University
of Cambridge, Cambridge, CB2 1TN, U.K.
| | - Ye Fan
- University
of Cambridge, Cambridge, CB2 1TN, U.K.
| | | | | | | | | | - Jeffrey B. Neaton
- University
of California Berkeley, Berkeley, California 94720, United States
- Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Steven G. Louie
- University
of California Berkeley, Berkeley, California 94720, United States
- Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Akshay Rao
- University
of Cambridge, Cambridge, CB2 1TN, U.K.
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Meng F, Donnelly C, Abert C, Skoric L, Holmes S, Xiao Z, Liao JW, Newton PJ, Barnes CH, Sanz-Hernández D, Hierro-Rodriguez A, Suess D, Cowburn RP, Fernández-Pacheco A. Non-Planar Geometrical Effects on the Magnetoelectrical Signal in a Three-Dimensional Nanomagnetic Circuit. ACS Nano 2021; 15:6765-6773. [PMID: 33848131 PMCID: PMC8155340 DOI: 10.1021/acsnano.0c10272] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Expanding nanomagnetism and spintronics into three dimensions (3D) offers great opportunities for both fundamental and technological studies. However, probing the influence of complex 3D geometries on magnetoelectrical phenomena poses important experimental and theoretical challenges. In this work, we investigate the magnetoelectrical signals of a ferromagnetic 3D nanodevice integrated into a microelectronic circuit using direct-write nanofabrication. Due to the 3D vectorial nature of both electrical current and magnetization, a complex superposition of several magnetoelectrical effects takes place. By performing electrical measurements under the application of 3D magnetic fields, in combination with macrospin simulations and finite element modeling, we disentangle the superimposed effects, finding how a 3D geometry leads to unusual angular dependences of well-known magnetotransport effects such as the anomalous Hall effect. Crucially, our analysis also reveals a strong role of the noncollinear demagnetizing fields intrinsic to 3D nanostructures, which results in an angular dependent magnon magnetoresistance contributing strongly to the total magnetoelectrical signal. These findings are key to the understanding of 3D spintronic systems and underpin further fundamental and device-based studies.
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Affiliation(s)
- Fanfan Meng
- Cavendish
Laboratory, University of Cambridge, Cambridge, CB3 0HE, U.K.
| | - Claire Donnelly
- Cavendish
Laboratory, University of Cambridge, Cambridge, CB3 0HE, U.K.
| | - Claas Abert
- Faculty
of Physics, University of Vienna, Vienna, 1090, Austria
- Research
Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1090, Austria
| | - Luka Skoric
- Cavendish
Laboratory, University of Cambridge, Cambridge, CB3 0HE, U.K.
| | - Stuart Holmes
- London
Centre for Nanotechnology, UCL, London, WC1H 0AH, U.K.
| | - Zhuocong Xiao
- Nanoscience
Centre, University of Cambridge, Cambridge, CB3 0FF, U.K.
| | - Jung-Wei Liao
- Cavendish
Laboratory, University of Cambridge, Cambridge, CB3 0HE, U.K.
| | - Peter J. Newton
- Cavendish
Laboratory, University of Cambridge, Cambridge, CB3 0HE, U.K.
| | | | - Dédalo Sanz-Hernández
- Cavendish
Laboratory, University of Cambridge, Cambridge, CB3 0HE, U.K.
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, Palaiseau, 91767, France
| | - Aurelio Hierro-Rodriguez
- Depto.
Física, Universidad de Oviedo, Oviedo, 33007, Spain
- SUPA,
School of Physics and Astronomy, University
of Glasgow, Glasgow, G12 8QQ, U.K.
| | - Dieter Suess
- Faculty
of Physics, University of Vienna, Vienna, 1090, Austria
- Research
Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1090, Austria
| | | | - Amalio Fernández-Pacheco
- Cavendish
Laboratory, University of Cambridge, Cambridge, CB3 0HE, U.K.
- SUPA,
School of Physics and Astronomy, University
of Glasgow, Glasgow, G12 8QQ, U.K.
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