DYNAMICS OF OPTICAL NONLINEARITIES INDUCED BY STRONG LIGHT ILLUMINATION IN CDS NANOCRYSTALLITES

Citation
E. Vanagas et al., DYNAMICS OF OPTICAL NONLINEARITIES INDUCED BY STRONG LIGHT ILLUMINATION IN CDS NANOCRYSTALLITES, Journal of applied physics, 81(8), 1997, pp. 3586-3591
Citations number
44
Categorie Soggetti
Physics, Applied
Journal title
ISSN journal
00218979
Volume
81
Issue
8
Year of publication
1997
Part
1
Pages
3586 - 3591
Database
ISI
SICI code
0021-8979(1997)81:8<3586:DOONIB>2.0.ZU;2-3
Abstract
Light induced grating experiments have been performed at room temperat ure in CdS nanocrystallites of 2.5 nm radius embedded in sol-gel glass films of different semiconductor volume concentration. The dynamics o f tile photogenerated carriers at the lowest transition peak has been shown to depend on the excitation intensity, No spatial diffusion is o bserved up to a nanocrystallite volume concentration of 35%. Below a f ew MW/cm(2) the carriers relax in each nanocrystallite, either radiati vely in similar to 150 ps or by trapping the electrons 15 meV below th eir excitation transition. For higher intensities of excitation, a sat uration of the excited stales occurs which allows the electrons to be trapped in the glass matrix, inducing a permanent grating by the creat ion of a static electric field. (C) 1997 American Institute of Physics .