Speaker
Description
Fully sp3 bonded carbon networks are highly promising candidates for wide-bandgap semiconductors, but their realization requires the complete elimination or passivation of residual sp2-hybridized atoms. The lack of long-range order makes the realization of 100% sp3 amorphous carbon a major challenge. While experiments have demonstrated that the structure of final carbon networks heavily depend on the initial precursors and processing pathways, with recent works achieving an sp3 fraction above 95% in bulk materials and above 80% in thin films, the underlying atomistic mechanisms remains poorly understood. A deep, atomistic understanding of how sp2 bonding is suppressed or transformed during the treatment is therefore essential to unlock a predictive pathway to maximize the sp3 fraction.
In this work, ab-initio molecular dynamics was applied to explore the theoretical blueprint for achieving the 100% sp3 amorphous limit without the inherent biases of predefined models or training data. We identify a specific temperature and pressure pathway for fabricating an ultra-high sp3 bulk material, which exhibits wide bandgap and high bulk modulus. Additionally, we investigate the formation mechanism of sp2 carbon atom ‘defects’ under biaxial stress condition, providing a physical explanation of why previous studies have been unable to surpass the 90% sp3 threshold in tetrahedral amorphous carbon thin films. These findings open a new avenue for designing high-performance, carbon-based materials with tailored electronic and mechanical properties.
| I am the presenting author | Yes |
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