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Electron Emission from Diamondoids: A Diffusion Quantum Monte Carlo Study

Research output: Contribution to journalJournal article


Article number096801
<mark>Journal publication date</mark>22/08/2005
<mark>Journal</mark>Physical Review Letters
Issue number9
Number of pages4
<mark>Original language</mark>English


We present density-functional theory (DFT) and quantum Monte Carlo (QMC) calculations designed to resolve experimental and theoretical controversies over the optical properties of H-terminated C nanoparticles (diamondoids). The QMC results follow the trends of well-converged plane-wave DFT calculations for the size dependence of the optical gap, but they predict gaps that are 1–2 eV higher. They confirm that quantum confinement effects disappear in diamondoids larger than 1 nm, which have gaps below that of bulk diamond. Our QMC calculations predict a small exciton binding energy and a negative electron affinity (NEA) for diamondoids up to 1 nm, resulting from the delocalized nature of the lowest unoccupied molecular orbital. The NEA suggests a range of possible applications of diamondoids as low-voltage electron emitters.

Bibliographic note

© 2005 The American Physical Society