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Spatial Control of Substitutional Dopants in Hexagonal Monolayer WS2: The Effect of Edge Termination |
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| Authors: | Tianyi Zhang Mingzu Liu Kazunori Fujisawa Michael Lucking Kory Beach Fu Zhang Maruda Shanmugasundaram Andrey Krayev William Murray Yu Lei Zhuohang Yu David Sanchez Zhiwen Liu Humberto Terrones Ana Laura Elías Mauricio Terrones |
| Affiliation: | 1. Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802 USA;2. Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802 USA
Department of Physics, The Pennsylvania State University, University Park, PA, 16802 USA;3. Research Initiative for Supra-Materials, Shinshu University, Nagano, 380–8553 Japan;4. Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180 USA;5. Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802 USA Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802 USA;6. HORIBA Instruments Inc, Piscataway, NJ, 08854 USA;7. HORIBA Instruments Inc, Novato, CA, 94949 USA;8. Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802 USA;9. Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802 USA Department of Physics, The Pennsylvania State University, University Park, PA, 16802 USA Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Shenzhen, 518055 China;10. Department of Physics, Binghamton University, Binghamton, NY, 13902 USA |
| Abstract: | The ability to control the density and spatial distribution of substitutional dopants in semiconductors is crucial for achieving desired physicochemical properties. Substitutional doping with adjustable doping levels has been previously demonstrated in 2D transition metal dichalcogenides (TMDs); however, the spatial control of dopant distribution remains an open field. In this work, edge termination is demonstrated as an important characteristic of 2D TMD monocrystals that affects the distribution of substitutional dopants. Particularly, in chemical vapor deposition (CVD)-grown monolayer WS2, it is found that a higher density of transition metal dopants is always incorporated in sulfur-terminated domains when compared to tungsten-terminated domains. Two representative examples demonstrate this spatial distribution control, including hexagonal iron- and vanadium-doped WS2 monolayers. Density functional theory (DFT) calculations are further performed, indicating that the edge-dependent dopant distribution is due to a strong binding of tungsten atoms at tungsten-zigzag edges, resulting in the formation of open sites at sulfur-zigzag edges that enable preferential dopant incorporation. Based on these results, it is envisioned that edge termination in crystalline TMD monolayers can be utilized as a novel and effective knob for engineering the spatial distribution of substitutional dopants, leading to in-plane hetero-/multi-junctions that display fascinating electronic, optoelectronic, and magnetic properties. |
| Keywords: | 2D transition metal dichalcogenides density functional theory doping edge termination heterogeneity in-plane heterostructures |