Trapping time of excitons in Si nanocrystals embedded in a SiO 2 matrix

E. M.L.D. De Jong*, W. D.A.M. De Boer, I. N. Yassievich, T. Gregorkiewicz

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Silicon (Si) nanocrystals (NCs) are of great interest for many applications, ranging from photovoltaics to optoelectonics. The photoluminescence quantum yield of Si NCs dispersed in SiO2 is limited, suggesting the existence of very efficient processes of nonradiative recombination, among which the formation of a self-trapped exciton state on the surface of the NC. In order to improve the external quantum efficiency of these systems, the carrier relaxation and recombination need to be understood more thoroughly. For that purpose, we perform transient-induced absorption spectroscopy on Si NCs embedded in a SiO2 matrix over a broad probe range for NCs of average sizes from 2.5 to 5.5 nm. The self-trapping of free excitons on surface-related states is experimentally and theoretically discussed and found to be dependent on the NC size. These results offer more insight into the self-trapped exciton state and are important to increase the optical performance of Si NCs.

Original languageEnglish
Article number195312
JournalPhysical Review B
Issue number19
Publication statusPublished - 22 May 2017
Externally publishedYes

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