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Excitons in silicon nanocrystallites: The nature of luminescence

2007; American Physical Society; Volume: 75; Issue: 3 Linguagem: Inglês

10.1103/physrevb.75.033303

1550-235X

Eleonora Luppi, Federico Iori, Rita Magri, Olivia Pulci, Stefano Ossicini, Elena Degoli, Valério Olevano,

Semiconductor materials and devices

The absorption and emission spectra of silicon nanocrystals up to $1\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ diameter have been calculated within a first-principles framework. Our calculations include geometry optimization and the many-body effects induced by the creation of an electron-hole pair. Starting from hydrogenated silicon clusters of different sizes, different $\mathrm{Si}∕\mathrm{O}$ bondings at the cluster surface have been considered. We found that the presence of a $\mathrm{Si}\mathrm{O}\mathrm{Si}$ bridge bond causes significant excitonic luminescence features in the visible range that are in fair agreement with experiment.