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Influence of boron doping and hydrogen passivation on recombination of photoexcited charge carriers in silicon nanocrystal/SiC multilayers

: Korinek, M.; Schnabel, M.; Canino, M.; Kozak, M.; Trojanek, F.; Salava, J.; Löper, P.; Janz, S.; Summonte, C.; Maly, P.


Journal of applied physics 114 (2013), Nr.7, Art.073101, 5 S.
ISSN: 0021-8979
ISSN: 1089-7550
European Commission EC
FP7-NMP; 245977; NASCENT
Charles University Grant Agency GAUK
GAUK 443911
Charles University Grant Agency GAUK
Fraunhofer ISE ()
Solarzellen - Entwicklung und Charakterisierung; Alternative Photovoltaik-Technologien; Neuartige Konzepte; Photoluminescence; Spectroscopy; carbide; nanocrystals

The influence of boron (B)-doping and remote plasma hydrogen passivation on the photoexcited charge carrier recombination in silicon nanocrystal/SiC multilayers was investigated in detail. The samples were prepared by high temperature annealing of amorphous (intrinsic and B-doped) Si1-xCx/SiC superlattices. The photoluminescence (PL) intensity of samples with B-doped silicon rich carbide layers was found to be up to two orders of magnitude larger and spectrally red shifted in comparison with that of the other samples. Hydrogen passivation leads to an additional increase in PL intensities. The PL decay can be described well by a mono-exponential function with a characteristic decay time of a few microseconds. This behavior agrees well with the picture of localized PL centers (surface states) together with the passivation of non-radiative defects by boron. The samples with B-doped SiC layers exhibit an additional PL band in the green spectral region that is quenched by hydrogen passivation. Its origin is attributed to defects due to suppression of crystallization of amorphous SiC layers as a result of B-doping. Measurement of ultrafast transient transmission allowed us to study the initial (picosecond) carrier dynamics. It was found to be dependent of pump intensity and interpreted in terms of multiparticle electron-hole recombination.