Laser heating effect on Raman spectra of Si nanocrystals embedded into SiOx matrix

• Published in: Semiconductor Physics Quantum Electronics & Optoelectronics
• Date: 2013
• Main Author: Nikolenko, A.S.
• Format: Article
• Language: English
• Published: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2013
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/117670
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Laser heating effect on Raman spectra of Si nanocrystals
 embedded into SiOx matrix /A.S. Nikolenko // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2013. — Т. 16, № 1. — С. 86-90. — Бібліогр.: 29 назв. — англ.

Influence of combined size confinement effect and effect of local laser heating
 on the first-order Raman spectrum of silicon nanocrystals embedded into SiOx matrix has
 been studied. Increase of the local temperature of Si nanocrystals caused by laser
 illumination with the power density up to 10 mW/μm² was estimated from the ratio of
 the Stokes/anti-Stokes peak intensities. Almost linear dependence of nanocrystals local
 temperature on the power density of exciting radiation with a rate of 63.6 Km² /mW has
 been found. The phonon line shape at power densities, when no laser heating effect is
 registered, was shown to be described well within the correlation length model of phonon
 confinement of Si nanocrystals with the size L = 9.2 nm. Observed phonon softening and
 broadening with increase of the exciting power density is considered as temperatureinduced vibration anharmonicity with the decay of optical phonons through three and four-phonon processes and corresponding anharmonic constants have been determined.