Controlling Vertical and Lateral Growth of Copper and Ruthenium on Tungsten Dichalcogenide Monolayers for Interconnects and Metal Contacts
- 1Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Ireland, T12 R5CP
Abstract
The unique properties of tungsten based transition metal dichalcogenide monolayers (TMDs) drive significant interest for their use in a variety of applications, from heterogeneous catalysis, to future generation semiconductor device technologies. In these technologies the TMD monolayers are necessarily interfaced with a metal, such as a source and drain contact for use as a channel material in sub-nm transistors, an interconnect metal when used as a diffusion barrier, or as a support for a metal catalyst. The control of the morphology of the interfaced metal is critical to ensure optimal material performance for these target applications. Therefore, an atomic level description of how metals interact and grow on TMDs is needed. First principles studies of metal-TMD monolayer interactions have primarily focussed on the behaviour of single metal atom adsorption, substitutional metal doping, or pristine metal-monolayer interfaces. Consequently, there persists a clear gap in the understanding of metal growth on TMD monolayers and the drivers of vertical versus lateral growth. In this work, we present a density functional theory and ab initio molecular dynamics investigation of the adsorption, preferred morphology, and dynamics of Cu and Ru metal deposits on WS2 and WSe2 monolayers. Using metal cluster models of sufficient size to display a variety of potential morphologies, and by characterising the behaviour of the metal deposits with an ensemble of analytical shape descriptors derived from the gyration tensor, we develop a comprehensive and quantitative understanding of the structure, stability, dynamics, and morphology of deposited metals on tungsten TMD monolayers. We find that on both TMDs Cu prefers to form compact, vertically growing clusters, with molecular dynamics simulations showing a transition to a more compact metal shape and a further promotion of 3D growth over time. In contrast, Ru prefers to grow laterally on WS2. Ru present on WSe2 displays a preference for a lateral morphology as on WS2, but makes noticeably more compact deposits on WSe2 than on WS2. Dynamics simulations show that temperature further promotes growth in the preferred direction, thus driving both island growth and lateral deposition depending on the inherent preference for a growth mode. These results demonstrate clearly how the identity of the metal and the TMD layer contribute to the preferred growth mode and morphology. Additionally, we reveal the critical importance of dynamic cluster evolution over time in determining the final structure.
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BibTeX
@misc{sweetman2026controlling,
title = {{Controlling Vertical and Lateral Growth of Copper and Ruthenium on Tungsten Dichalcogenide Monolayers for Interconnects and Metal Contacts}},
author = {Michael Sweetman and Cara-Lena Nies and Michael Nolan and Nolan Michael},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15002126/v2},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15002126/v2},
note = {CC BY},
}
RIS
TY - UNPB
TI - Controlling Vertical and Lateral Growth of Copper and Ruthenium on Tungsten Dichalcogenide Monolayers for Interconnects and Metal Contacts
AU - Michael Sweetman
AU - Cara-Lena Nies
AU - Michael Nolan
AU - Nolan Michael
PY - 2026
DA - 2026/10/19
PB - ChemRxiv
DO - 10.26434/chemrxiv.15002126/v2
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15002126/v2
AB - The unique properties of tungsten based transition metal dichalcogenide monolayers (TMDs) drive significant interest for their use in a variety of applications, from heterogeneous catalysis, to future generation semiconductor device technologies. In these technologies the TMD monolayers are necessarily interfaced with a metal, such as a source and drain contact for use as a channel material in sub-nm transistors, an interconnect metal when used as a diffusion barrier, or as a support for a metal catalyst. The control of the morphology of the interfaced metal is critical to ensure optimal material performance for these target applications. Therefore, an atomic level description of how metals interact and grow on TMDs is needed. First principles studies of metal-TMD monolayer interactions have primarily focussed on the behaviour of single metal atom adsorption, substitutional metal doping, or pristine metal-monolayer interfaces. Consequently, there persists a clear gap in the understanding of metal growth on TMD monolayers and the drivers of vertical versus lateral growth. In this work, we present a density functional theory and ab initio molecular dynamics investigation of the adsorption, preferred morphology, and dynamics of Cu and Ru metal deposits on WS2 and WSe2 monolayers. Using metal cluster models of sufficient size to display a variety of potential morphologies, and by characterising the behaviour of the metal deposits with an ensemble of analytical shape descriptors derived from the gyration tensor, we develop a comprehensive and quantitative understanding of the structure, stability, dynamics, and morphology of deposited metals on tungsten TMD monolayers. We find that on both TMDs Cu prefers to form compact, vertically growing clusters, with molecular dynamics simulations showing a transition to a more compact metal shape and a further promotion of 3D growth over time. In contrast, Ru prefers to grow laterally on WS2. Ru present on WSe2 displays a preference for a lateral morphology as on WS2, but makes noticeably more compact deposits on WSe2 than on WS2. Dynamics simulations show that temperature further promotes growth in the preferred direction, thus driving both island growth and lateral deposition depending on the inherent preference for a growth mode. These results demonstrate clearly how the identity of the metal and the TMD layer contribute to the preferred growth mode and morphology. Additionally, we reveal the critical importance of dynamic cluster evolution over time in determining the final structure.
ER -