First-principles study of distance-dependent electronic coupling in TMD–metal interfaces

Abdul Ghaffar; Ryo Maezono; Kenta Hongo

doi:10.1016/j.commatsci.2026.114512

First-principles study of distance-dependent electronic coupling in TMD–metal interfaces

Abdul Ghaffar
, Ryo Maezono
, Kenta Hongo

Research output: Contribution to journal › Article › peer-review

Abstract

Parasitic contact resistance remains a major obstacle to the performance of 2D transition metal dichalcogenide (TMD)–semiconductor interfaces. A key reason for this is Fermi-level pinning (FLP), which arises from metal-induced gap states (MIGS) that extend into the semiconductor bandgap. This problem is particularly severe when using high-work-function metals such as gold (Au), palladium (Pd), and platinum (Pt). TMD contacts with these high-work-function metals make it difficult to achieve the p-type Schottky barrier height (SBH). Several strategies have been proposed to address this issue, including inserting dielectric or semimetallic layers at the interface to suppress MIGS. However, the specific role of interface separation in modifying contact properties has not been thoroughly studied. In this work, we use first-principles calculations to investigate how the distance between the metal and the semiconductor affects FLP, MIGS suppression, and key barrier properties. We focus on metal–semiconductor interfaces involving high-work-function metals (Au, Pd, Pt) and two commonly studied TMDs: WS₂ and MoS₂. We analyze how SBH, tunnel barrier height (TBH), band bending, MIGS penetration, and the Fermi-level pinning index (S) change as the interface distance increases. Our results show that increasing the separation between the metal and semiconductor systematically reduces MIGS. This weakens FLP and allows the SBH to depend more directly on the metal’s work function. As a result, SBH polarity can be aligned with predictions from the Schottky–Mott limit, enabling the design of both n-type and p-type contacts. We also calculate band bending to understand how charge transfers across the interface. Overall, our findings provide critical insight into the role of interface separation in 2D metal–semiconductor contacts. This study can serve as a foundation for future research aimed at improving contact performance and overall device efficiency.

Original language	English
Article number	114512
Journal	Computational Materials Science
Volume	265
DOIs	https://doi.org/10.1016/j.commatsci.2026.114512
State	Published - Feb 20 2026
Externally published	Yes

Funding

The computations in this study were conducted using the facilities of the Research Center for Advanced Computing Infrastructure (RCACI) at JAIST. A.G. would like to extend his gratitude to the Ministry of Education, Culture, Sports, Science and Technology (MEXT) for the financial support through the MEXT scholarship, which has been instrumental in facilitating and advancing our research endeavors. R.M. acknowledges financial support from MEXT-KAKENHI (JP22H05146, JP21K03400, and JP19H04692), the Air Force Office of Scientific Research (AFOSR-AOARD/FA2386-17-1-4049; FA2386-19-1-4015), and JSPS Bilateral Joint Projects (JPJSBP120197714). K.H. is thankful for financial support from MEXT-KAKENHI , Japan (JP19K05029, JP21K03400, JP22H02170, and JP23H04623), and the Air Force Office of Scientific Research, United States (Award Numbers: FA2386-22-1-4065).

Keywords

Band bending
Fermi-level pinning
Interface engineering
Metal-induced gap states
Schottky barrier
Transition metal dichalcogenides
Tunnel barrier

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10.1016/j.commatsci.2026.114512

Cite this

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title = "First-principles study of distance-dependent electronic coupling in TMD–metal interfaces",

abstract = "Parasitic contact resistance remains a major obstacle to the performance of 2D transition metal dichalcogenide (TMD)–semiconductor interfaces. A key reason for this is Fermi-level pinning (FLP), which arises from metal-induced gap states (MIGS) that extend into the semiconductor bandgap. This problem is particularly severe when using high-work-function metals such as gold (Au), palladium (Pd), and platinum (Pt). TMD contacts with these high-work-function metals make it difficult to achieve the p-type Schottky barrier height (SBH). Several strategies have been proposed to address this issue, including inserting dielectric or semimetallic layers at the interface to suppress MIGS. However, the specific role of interface separation in modifying contact properties has not been thoroughly studied. In this work, we use first-principles calculations to investigate how the distance between the metal and the semiconductor affects FLP, MIGS suppression, and key barrier properties. We focus on metal–semiconductor interfaces involving high-work-function metals (Au, Pd, Pt) and two commonly studied TMDs: WS2 and MoS2. We analyze how SBH, tunnel barrier height (TBH), band bending, MIGS penetration, and the Fermi-level pinning index (S) change as the interface distance increases. Our results show that increasing the separation between the metal and semiconductor systematically reduces MIGS. This weakens FLP and allows the SBH to depend more directly on the metal{\textquoteright}s work function. As a result, SBH polarity can be aligned with predictions from the Schottky–Mott limit, enabling the design of both n-type and p-type contacts. We also calculate band bending to understand how charge transfers across the interface. Overall, our findings provide critical insight into the role of interface separation in 2D metal–semiconductor contacts. This study can serve as a foundation for future research aimed at improving contact performance and overall device efficiency.",

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author = "Abdul Ghaffar and Ryo Maezono and Kenta Hongo",

note = "Publisher Copyright: {\textcopyright} 2026 The Authors.",

year = "2026",

month = feb,

day = "20",

doi = "10.1016/j.commatsci.2026.114512",

language = "English",

volume = "265",

journal = "Computational Materials Science",

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TY - JOUR

T1 - First-principles study of distance-dependent electronic coupling in TMD–metal interfaces

AU - Ghaffar, Abdul

AU - Maezono, Ryo

AU - Hongo, Kenta

PY - 2026/2/20

Y1 - 2026/2/20

N2 - Parasitic contact resistance remains a major obstacle to the performance of 2D transition metal dichalcogenide (TMD)–semiconductor interfaces. A key reason for this is Fermi-level pinning (FLP), which arises from metal-induced gap states (MIGS) that extend into the semiconductor bandgap. This problem is particularly severe when using high-work-function metals such as gold (Au), palladium (Pd), and platinum (Pt). TMD contacts with these high-work-function metals make it difficult to achieve the p-type Schottky barrier height (SBH). Several strategies have been proposed to address this issue, including inserting dielectric or semimetallic layers at the interface to suppress MIGS. However, the specific role of interface separation in modifying contact properties has not been thoroughly studied. In this work, we use first-principles calculations to investigate how the distance between the metal and the semiconductor affects FLP, MIGS suppression, and key barrier properties. We focus on metal–semiconductor interfaces involving high-work-function metals (Au, Pd, Pt) and two commonly studied TMDs: WS2 and MoS2. We analyze how SBH, tunnel barrier height (TBH), band bending, MIGS penetration, and the Fermi-level pinning index (S) change as the interface distance increases. Our results show that increasing the separation between the metal and semiconductor systematically reduces MIGS. This weakens FLP and allows the SBH to depend more directly on the metal’s work function. As a result, SBH polarity can be aligned with predictions from the Schottky–Mott limit, enabling the design of both n-type and p-type contacts. We also calculate band bending to understand how charge transfers across the interface. Overall, our findings provide critical insight into the role of interface separation in 2D metal–semiconductor contacts. This study can serve as a foundation for future research aimed at improving contact performance and overall device efficiency.

AB - Parasitic contact resistance remains a major obstacle to the performance of 2D transition metal dichalcogenide (TMD)–semiconductor interfaces. A key reason for this is Fermi-level pinning (FLP), which arises from metal-induced gap states (MIGS) that extend into the semiconductor bandgap. This problem is particularly severe when using high-work-function metals such as gold (Au), palladium (Pd), and platinum (Pt). TMD contacts with these high-work-function metals make it difficult to achieve the p-type Schottky barrier height (SBH). Several strategies have been proposed to address this issue, including inserting dielectric or semimetallic layers at the interface to suppress MIGS. However, the specific role of interface separation in modifying contact properties has not been thoroughly studied. In this work, we use first-principles calculations to investigate how the distance between the metal and the semiconductor affects FLP, MIGS suppression, and key barrier properties. We focus on metal–semiconductor interfaces involving high-work-function metals (Au, Pd, Pt) and two commonly studied TMDs: WS2 and MoS2. We analyze how SBH, tunnel barrier height (TBH), band bending, MIGS penetration, and the Fermi-level pinning index (S) change as the interface distance increases. Our results show that increasing the separation between the metal and semiconductor systematically reduces MIGS. This weakens FLP and allows the SBH to depend more directly on the metal’s work function. As a result, SBH polarity can be aligned with predictions from the Schottky–Mott limit, enabling the design of both n-type and p-type contacts. We also calculate band bending to understand how charge transfers across the interface. Overall, our findings provide critical insight into the role of interface separation in 2D metal–semiconductor contacts. This study can serve as a foundation for future research aimed at improving contact performance and overall device efficiency.

KW - Band bending

KW - Fermi-level pinning

KW - Interface engineering

KW - Metal-induced gap states

KW - Schottky barrier

KW - Transition metal dichalcogenides

KW - Tunnel barrier

UR - https://www.scopus.com/pages/publications/105028330091

U2 - 10.1016/j.commatsci.2026.114512

DO - 10.1016/j.commatsci.2026.114512

M3 - Article

AN - SCOPUS:105028330091

SN - 0927-0256

VL - 265

JO - Computational Materials Science

JF - Computational Materials Science

M1 - 114512

ER -

First-principles study of distance-dependent electronic coupling in TMD–metal interfaces

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Keywords

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