Far-infrared spectroscopy of folded transverse acoustic phonons in 4H–SiC

Shalygin, V. A.; Adamov, R. B.; Moldavskaya, M. D.; Vinnichenko, M. Ya.; Firsov, D. A.

doi:10.1063/5.0031064

Cited by 2 publications

(1 citation statement)

References 16 publications

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“…These results reveal that the surface vibration mode of SiO is IR active, so it can act as the fingerprint mode for identifying the SiO bond on the surface of the SiC QD. The nature of the optical and acoustic phonon modes in SiC has always been a concern …”

Section: Resultsmentioning

confidence: 99%

Core and Surface Electronic States and Phonon Modes in SiC Quantum Dots Studied by Optical Spectroscopy and Hybrid TDDFT

Liu

Liang

et al. 2021

J. Phys. Chem. C

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The surface of the SiC quantum dot (QD) is a complex two-dimensional system that comprises fruitful surface reconstruction and passivation which affect its chemistry and photophysics. Here, we report the novel yellow fluorescence (2.19 eV) of the colloidal SiC QDs in the quantum confinement regime, which decays much slowly (lifetime > 70 ns) compared with the previously observed blue-green fluorescence (<15 ns). The semi-empirical and time-dependent density functional theory calculations reveal that it originates from the trapped surface states at the SiO bond, whose energy levels lie in the forbidden gap of the SiC QD. There exists multiple splitting of the transverse and longitudinal optical phonon modes of the SiC QD, and there is an infrared active fingerprint surface mode belonging to the SiO bond. The calculations agree well with the experiments. These findings highly improve our understanding of the surface properties of the SiC QDs.

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Section: Resultsmentioning

confidence: 99%

Core and Surface Electronic States and Phonon Modes in SiC Quantum Dots Studied by Optical Spectroscopy and Hybrid TDDFT

Liu

Liang

et al. 2021

J. Phys. Chem. C

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Optical access to folded transverse acoustic phonon doublet in 6H-SiC

Shalygin

Adamov

Vinnichenko

et al. 2021

Journal of Applied Physics

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We report on the study of far-infrared transmission in silicon carbide of 6H polytype in the region of IR active folded transverse acoustic (FTA) phonon doublet. Joint analysis of the transmittance spectra obtained at low and high resolutions is performed to determine spectral dependences of the refractive index and absorption coefficient. A dual Lorentz oscillator model is used to simulate the FTA phonon contributions to the dielectric function. The oscillator strengths and phonon lifetimes for both the components of the FTA phonon doublet in 6H-SiC are determined. At temperature decrease from 300 to 5 K, the FTA phonon lifetimes increase more than six times, while the oscillator strengths remain the same.

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Far-infrared spectroscopy of folded transverse acoustic phonons in 4H–SiC

Cited by 2 publications

References 16 publications

Core and Surface Electronic States and Phonon Modes in SiC Quantum Dots Studied by Optical Spectroscopy and Hybrid TDDFT

Core and Surface Electronic States and Phonon Modes in SiC Quantum Dots Studied by Optical Spectroscopy and Hybrid TDDFT

Optical access to folded transverse acoustic phonon doublet in 6H-SiC

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