L304
Synthesis of Si nanoparticles with Visible Photoluminescence and Dynamics of Laser Ablation
Kouichi Murakami
Institute of Materials Science,
University of Tsukuba
In order to synthesize chemically clean silicon nanoparticles exhibiting high
intensity of visible photoluminesecence (PL), we have formed Si nanoparticles
by laser ablation in ambient inert gas, investigated dynamics of the formation
of the particles by time-resolved soft X-ray absorption and photoemission
measurements, and performed PL measurements at room temperature for two
types of samples.
The first is SiO2 film including Si nanocrystals that are formed through
annealing deposited SiOx films at high temperatures. This system shows strong
PL ranging from 1.4eV to 1.8eV. It is likely that the PL peak energy depends on the
size of Si nanocrystals and the initial value of x in the deposited SiOx films.
The second is Si nanoparticle-film which consists of Si nanoparticles whose
surrounding are oxidized. This system also gives a broad PL with a peak at approxi-
mately 1.5 eV. From various kinds of time-resolved structure measurements, it has
been recently clarified when, where or how Si nanoparticles are formed after ns
pulsed-laser ablation.
We will demonstrate merits of laser ablation technique, and discuss dynamics of the
formation process of Si nanoparticle, and propose a novel surface modification method
to obtain Si nanoparticle system with high efficient visible PL.
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