Interfacial disorder and optoelectronic properties of diamond nanocrystals

TitleInterfacial disorder and optoelectronic properties of diamond nanocrystals
Publication TypeJournal Article
Year of Publication2009
AuthorsVantarakis G, Mathioudakis C, Kopidakis G, Wang CZ, Ho KM, Kelires PC
Journal TitlePhysical Review B
Date Published07/01
ISBN Number1098-0121
Accession NumberISI:000268618100066
Keywordsdynamics, electronic-properties, model, optical-properties, simulations, tetrahedral amorphous-carbon

We present in this work a theoretical framework based on the tight-binding method, which is able to probe at a local atomic level the optoelectronic response of nanomaterial systems and link it to the associated disorder. We apply this methodology to carbon nanocomposites containing diamond nanocrystals. We find that significant structural and topological disorder exists at the interface between the nanodiamonds and the embedding amorphous carbon matrix. This can be quantitatively probed by extracting the Urbach energies from the optical parameters. Disorder in the nanocrystals appears in their outer shell near the interface and is manifested as bond length and angle distortions. Energetics and stability analysis show that nanodiamonds embedded in matrices with high density and high fraction of fourfold coordinated atoms are more stable.

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