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Dielectric function and optical transitions of silicon nanocrystals between 0.6 eV and 6.5 eV
Author(s) -
Mansour M.,
En Naciri A.,
Johann L.,
Grob J. J.,
Stchakovsky M.
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200777762
Subject(s) - silicon , dielectric , materials science , wavelength , nanocrystal , amplitude , ellipsometry , dielectric function , analytical chemistry (journal) , optics , optoelectronics , nanotechnology , chemistry , thin film , physics , chromatography
In this work, we report on the study of the dielectric function of nanocrystal silicon (nc‐Si) implanted in a SiO 2 matrix on a silicon substrate by spectroscopic ellipsometry (SE). The formed nc‐Si have an average size around 4 nm. The SE measurements are performed at an angle of incidence of 70° in air at room temperature and in the spectral range of 0.6 eV to 6.5 eV. Two models are used to extract the optical responses of nc‐Si: Forouhi–Bloomer formalism and wavelength‐by‐wavelength inversion. The nc‐Si exhibits a significant reduction in the dielectric functions in comparison with the bulk Si. We have observed a reduction of the amplitude of the E 1 transition with a very weak shift of its energy position. The transition E 2 is characterized by a rather broad peak with an amplitude greater than that of E 1 . (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)