Toh Chee Tat

@article{ISI:001498039100001,
title = {Superior Adhesion of Monolayer Amorphous Carbon to Copper},
author = {Hongji Zhang and Artem K Grebenko and Konstantin V Iakoubovskii and Hanning Zhang and Ruslan Yamaletdinov and Anna Makarova and Alexander Fedorov and S K Rejaul and Ranjith Shivajirao and Zheng Jue Tong and Sergey Grebenchuk and Ugur Karadeniz and Lu Shi and Denis V Vyalikh and Ya He and Andrei Starkov and Alena A Alekseeva and Chuan Chu Tee and Carlo Mendoza Orofeo and Junhao Lin and Kazutomo Suenaga and Michel Bosman and Maciej Koperski and Bent Weber and Kostya S Novoselov and Oleg V Yazyev and Chee-Tat Toh and Barbaros Ozyilmaz},
doi = {10.1002/adma.202419112},
times_cited = {0},
issn = {0935-9648},
year = {2025},
date = {2025-05-29},
journal = {ADVANCED MATERIALS},
publisher = {WILEY-V C H VERLAG GMBH},
address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
abstract = {The single-atom thickness of graphene holds great potential for device scaling, but its effectiveness as a thin metal-ion diffusion barrier in microelectronics and a corrosion barrier for plasmonic devices is compromised by weak van der Waals interactions with copper (Cu), leading to delamination issues. In contrast, monolayer amorphous carbon (MAC), a recently reported single-atom-thick carbon film with a disordered sp2 hybridized structure, demonstrates superior adhesion properties. This study reveals that MAC exhibits an adhesion energy of 85 J m-2 on Cu, which is 13 times greater than that of graphene. This exceptional adhesion is attributed to the formation of covalent-like Cu & horbar;C bonds while preserving its sp2 structure, as evidenced by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Density functional theory (DFT) calculations further elucidate that the corrugated structure of MAC facilitates the hybridization of C 2pz orbitals with Cu 4s and 3dz2 orbitals, promoting strong bonding. These insights indicate that the amorphous structure of MAC significantly enhances adhesion while preserving its elemental composition, providing a pathway to improve the mechanical reliability and performance of two-dimensional (2D) materials on metal substrates in various technological applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:001462473000001,
title = {Intrinsic toughening in monolayer amorphous carbon nanocomposites},
author = {Bongki Shin and Bo Ni and Chee-Tat Toh and Doug Steinbach and Zhenze Yang and Lucas M Sassi and Qing Ai and Kangdi Niu and Junhao Lin and Kazu Suenaga and Yimo Han and Markus J Buehler and Barbaros Ozyilmaz and Jun Lou},
doi = {10.1016/j.matt.2025.102000},
times_cited = {2},
issn = {2590-2393},
year = {2025},
date = {2025-04-02},
journal = {MATTER},
volume = {8},
number = {4},
publisher = {CELL PRESS},
address = {50 HAMPSHIRE ST, FLOOR 5, CAMBRIDGE, MA 02139 USA},
abstract = {Two-dimensional (2D) materials have immense potential to advance flexible electronics, yet they are limited by low fracture toughness. This study addresses the intrinsic toughening of monolayer amorphous carbon (MAC), a 2D nanocomposite, to overcome this challenge. By incorporating both amorphous and nanocrystalline phases, MAC significantly enhances energy absorption during fracture propagation, as evidenced by crack blunting, deflecting, and bridging. Using in situ tensile tests under a scanning electron microscope, our results indicate an 8-fold increase in the energy release rate compared to monolayer graphene, along with improved fracture strain and crack stability. Molecular dynamics simulations demonstrate the impact of phase composition on fracture energy. Our results present a scalable toughening strategy for 2D materials, potentially broadening their applications in fields requiring robust fracture resistance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}