Contacts to Two-dimensional Materials: Image Forces, Dielectric Environment, and Back-gate

Brahma, Madhuchhanda; Put, Maarten L. Van de; Chen, Edward; Fischetti, Massimo V.; Vandenberghe, William G.

doi:10.1109/vlsi-tsa54299.2022.9770997

Cited by 1 publication

(2 citation statements)

References 6 publications

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“…[7][8][9][10] However, the future use of 2D semiconducting materials for electronic device applications hinges on the ability to make low-resistance contacts. 1,[11][12][13][14] A significant amount of attention has recently been paid to the theoretical modeling of contact resistance in 2D materials. 15,16 A prevalent approach is to use first principles density-functional theory (DFT) quantum transport simulations.…”

Section: Metalmentioning

confidence: 99%

“…we have shown that IFBL can be more important in contacts to 2D materials because it is mainly the permittivity (ε) of the surrounding material that controls the barrier lowering. 13 Using a lowpermittivity dielectric can lower the metal-semiconductor barrier by up to a factor of 50. 24 Figure 1a-b shows two configurations for a metal to contact a 2D material where Fig.…”

Section: Metalmentioning

confidence: 99%

See 1 more Smart Citation

Image-Force Barrier Lowering for Two-Dimensional Materials: Direct Determination and Method of Images on a Cone Manifold

Evans¹,

Deylgat²,

Chen³

et al. 2023

Preprint

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The future use of two-dimensional (2D) semiconducting materials for electronic device applications hinges on the ability to make low-resistance contacts. To model such contacts, an accurate expression of the image-force barrier-lowering (IFBL) is needed. We derive the image-force energy by solving Poisson's equation with the boundary conditions of two metal surfaces separated by an angle Ω. We show how the image-force energy can also be obtained using the method of images provided a non-Euclidian cone-manifold space is used. We calculate how much the IFBL is strengthened or weakened for various Ω and angles with the 2D semiconductor. For the most prominent 2D material contact configuration, the image-force energy is reduced by a factor 6 − 2/ √ 3 ≈ 0.85, but a smaller angle between the metal surfaces can significantly increase the image-force energy. We predict that a contact with a small angle between the metal and 2D material and a surrounding dielectric with low permittivity will yield low contact resistance by enhancing IFBL.

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