The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materials
Abstract The performance of transistors based on two-dimensional (2D) materials is affected largely by the contact resistance due to high Schottky barriers at the metal-2D-material interface. In this work, we incorporate the effect of surrounding dielectrics and image-force barrier-lowering in calcu...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2023-03-01
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| Series: | npj 2D Materials and Applications |
| Online Access: | https://doi.org/10.1038/s41699-023-00372-6 |
| _version_ | 1797864579811770368 |
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| author | Madhuchhanda Brahma Maarten L. Van de Put Edward Chen Massimo V. Fischetti William G. Vandenberghe |
| author_facet | Madhuchhanda Brahma Maarten L. Van de Put Edward Chen Massimo V. Fischetti William G. Vandenberghe |
| author_sort | Madhuchhanda Brahma |
| collection | DOAJ |
| description | Abstract The performance of transistors based on two-dimensional (2D) materials is affected largely by the contact resistance due to high Schottky barriers at the metal-2D-material interface. In this work, we incorporate the effect of surrounding dielectrics and image-force barrier-lowering in calculating the resistance of Schottky edge-contacts between a metal and a transition-metal dichalcogenide (TMD) thin layer. The electrostatic potential is computed by solving the Poisson equation numerically. The transmission probability is computed using the Wentzel–Kramers–Brillouin (WKB) approximation using the full-band density of states obtained from density functional theory (DFT). The effect of the image force is obtained analytically using the Coulomb kernel of a point charge with boundary conditions appropriate to the geometry we have considered. We find that the image-force barrier-lowering (IFBL) in edge-contacts is determined mainly by the dielectric permittivity of the surrounding oxide. We find that low-κ surrounding dielectrics are crucial for obtaining low resistance monolayer-TMD edge-contacts. Our results show metal-to-n(p)-type MoS2 (WSe2) edge-contacts with SiO2 as top and bottom insulators, a doping concentration > 1 × 1013cm−2 and a metal work-function < 5.1 eV ( > 4.6 eV) result in a contact resistance as low as 50 Ω ⋅ μm. |
| first_indexed | 2024-04-09T22:54:10Z |
| format | Article |
| id | doaj.art-aa69af3fad69486db325cfa8ee4c7c5b |
| institution | Directory Open Access Journal |
| issn | 2397-7132 |
| language | English |
| last_indexed | 2024-04-09T22:54:10Z |
| publishDate | 2023-03-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj 2D Materials and Applications |
| spelling | doaj.art-aa69af3fad69486db325cfa8ee4c7c5b2023-03-22T11:22:45ZengNature Portfolionpj 2D Materials and Applications2397-71322023-03-01711910.1038/s41699-023-00372-6The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materialsMadhuchhanda Brahma0Maarten L. Van de Put1Edward Chen2Massimo V. Fischetti3William G. Vandenberghe4Department of Materials Science and Engineering, The University of Texas at DallasDepartment of Materials Science and Engineering, The University of Texas at DallasCorporate Research, Taiwan Semiconductor Manufacturing Company Ltd.Department of Materials Science and Engineering, The University of Texas at DallasDepartment of Materials Science and Engineering, The University of Texas at DallasAbstract The performance of transistors based on two-dimensional (2D) materials is affected largely by the contact resistance due to high Schottky barriers at the metal-2D-material interface. In this work, we incorporate the effect of surrounding dielectrics and image-force barrier-lowering in calculating the resistance of Schottky edge-contacts between a metal and a transition-metal dichalcogenide (TMD) thin layer. The electrostatic potential is computed by solving the Poisson equation numerically. The transmission probability is computed using the Wentzel–Kramers–Brillouin (WKB) approximation using the full-band density of states obtained from density functional theory (DFT). The effect of the image force is obtained analytically using the Coulomb kernel of a point charge with boundary conditions appropriate to the geometry we have considered. We find that the image-force barrier-lowering (IFBL) in edge-contacts is determined mainly by the dielectric permittivity of the surrounding oxide. We find that low-κ surrounding dielectrics are crucial for obtaining low resistance monolayer-TMD edge-contacts. Our results show metal-to-n(p)-type MoS2 (WSe2) edge-contacts with SiO2 as top and bottom insulators, a doping concentration > 1 × 1013cm−2 and a metal work-function < 5.1 eV ( > 4.6 eV) result in a contact resistance as low as 50 Ω ⋅ μm.https://doi.org/10.1038/s41699-023-00372-6 |
| spellingShingle | Madhuchhanda Brahma Maarten L. Van de Put Edward Chen Massimo V. Fischetti William G. Vandenberghe The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materials npj 2D Materials and Applications |
| title | The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materials |
| title_full | The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materials |
| title_fullStr | The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materials |
| title_full_unstemmed | The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materials |
| title_short | The importance of the image forces and dielectric environment in modeling contacts to two-dimensional materials |
| title_sort | importance of the image forces and dielectric environment in modeling contacts to two dimensional materials |
| url | https://doi.org/10.1038/s41699-023-00372-6 |
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