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Efficient Photoluminescence Upconversion in Porous Si
Author(s) -
Künzner N.,
Kovalev D.,
Heckler H.,
Diener J.,
Polisski G.,
Koch F.,
Efros Al.L.,
Rosen M.
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200103)224:1<21::aid-pssb21>3.0.co;2-w
Subject(s) - photoluminescence , photon upconversion , nanocrystal , excitation , materials science , porosity , intensity (physics) , stokes shift , optoelectronics , photoluminescence excitation , nanotechnology , optics , luminescence , composite material , physics , quantum mechanics
Abstract We report on a new phenomenon specific for a system of spatially interconnected nanocrystal assemblies: efficient low temperature photoluminescence (PL) upconversion at resonant optical excitation of porous Si. The upconverted photoluminescence (anti‐Stokes PL) is observed at intensities as low as 0.1 W/cm 2 and its intensity is as large as that of the Stokes PL band. The confirmation of the essence of connectivity between nanocrystals comes from the same type of studies performed on systems containing Si nanocrystals surrounded by a thick SiO 2 shell where the anti‐Stokes PL is completely absent for any excitation energy and intensity used while the properties of the Stokes PL are very similar to those of porous Si.