Electron Emission from Diamondoids: A Diffusion Quantum Monte Carlo Study
Abstract
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.
Cite
@article{arxiv.0801.0381,
title = {Electron Emission from Diamondoids: A Diffusion Quantum Monte Carlo Study},
author = {N. D. Drummond and A. J. Williamson and R. J. Needs and G. Galli},
journal= {arXiv preprint arXiv:0801.0381},
year = {2008}
}