Raman diagnostics of photoinduced heating of silicon nanowires prepared by metal-assisted chemical etchingстатья
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Дата последнего поиска статьи во внешних источниках: 20 января 2016 г.
Аннотация:Raman spectroscopy was applied to investigate
laser-induced heating of silicon nanowires (SiNWs) formed
by metal-assisted chemical etching of lightly boron-doped
crystalline silicon (c-Si) wafers. Low-frequency shift of
the Raman peak from 520.5 cm−1 to about 517 cm−1
for SiNWs with length of 40–65 µm under laser irradiation
with wavelengths of 632.8 or 488 nm was observed, and
it was explained by an increase in the average temperature
of SiNWs on about 150 K for the laser intensity about
1 kW/cm2 . The same photoinduced heating was confirmed
by analyzing the ratio between the Stokes and anti-Stokes
components of the Raman scattering. The obtained experimental
data allow us to estimate the thermal conductivity
coefficient of SiNW array ~0.1 W/(m K), which is three
orders of magnitude smaller than that of c-Si. Furthermore,
the Raman spectra of SiNWs under excitation with
intensity above 0.2–0.5 kW/cm2 consisted of an additional
low-frequency peak, which is related to an overheated subsystem
of well spatially separated fine SiNWs up to 600–
700 K. The observed strong photoinduced heating can be
used for local laser-induced treatment of SiNWs and biomedical
applications.