Optical studies of silicon nanocrystals in colloidal and sol-gel matrices

Howard W H Lee, Jeffrey E. Davis, Margaret L. Olsen, Susan M. Kauzlarich, Richard A. Bley, Subhash H. Risbud, David J. Duval

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations


We studied the optical properties of silicon nanocrystals incorporated into colloidal and sol-gel matrices. The silicon nanocrystals are produced by ultrasonic dispersion of porous silicon layers. We report results on the dependence of the photoluminescence (PL) spectra with excitation intensity. The PL shows a blue peak (at approx. 415-460 nm) and a red peak (at approx. 680 nm). This PL spectrum shows a remarkable dependence on the excitation intensity. As the intensity is increased, the blue peak grows at the expense of the red. A model is suggested for this behavior. We also report on the excitation intensity dependence and the emission wavelength dependence of the PL decay at low (1 kHz) and high (82 MHz) repetition rates of optical excitation. When low repetition rate excitation is used, the PL decay times are all exponential, short (ns), and appear to vary little with emission wavelength. This sharply contrasts with what is observed in porous silicon. With high repetition rate excitation, both red and blue peaks show long (100's ns) and short (ps-ns) lifetime components. We contrast the different optical properties of these silicon nanocrystals with that observed in porous silicon.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
PublisherMaterials Research Society
Number of pages6
StatePublished - 1994
Externally publishedYes
EventProceedings of the 1994 MRS Symposium - San Francisco, CA, USA
Duration: Apr 4 1994Apr 8 1994


OtherProceedings of the 1994 MRS Symposium
CitySan Francisco, CA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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