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arXiv · 0901.4268

Direct bandgap optical transitions in Si nanocrystals

A. A. Prokofiev·A. S. Moskalenko·I. N. Yassievich·W. D. A. M. de Boer·D. Timmerman·H. Zhang·W. J. Buma·T. Gregorkiewicz
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Abstract

The effect of quantum confinement on the direct bandgap of spherical Si nanocrystals has been modelled theoretically. We conclude that the energy of the direct bandgap at the $\Gamma$-point decreases with size reduction: quantum confinement enhances radiative recombination across the direct bandgap and introduces its "red" shift for smaller grains. We postulate to identify the frequently reported efficient blue emission (F-band) from Si nanocrystals with this zero-phonon recombination. In a dedicated experiment, we confirm the "red" shift of the F-band, supporting the proposed identification.

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A. A. Prokofiev, A. S. Moskalenko, I. N. Yassievich, W. D. A. M. de Boer, D. Timmerman, H. Zhang, W. J. Buma, T. Gregorkiewicz. 2009-01-27. Direct bandgap optical transitions in Si nanocrystals. https://doi.org/10.1134/s0021364009240059

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