Publication:
Vibrational Analysis of Silicon Nanoparticles Using Simulation and Decomposition of Raman Spectra

Дата
2020
Авторы
Povarnitsyn, M. E.
Shcheblanov, N. S.
Ivanov, D. S.
Timoshenko, V. Y.
Klimentov, S. M.
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Издатель
Научные группы
Организационные подразделения
Организационная единица
Инженерно-физический институт биомедицины
Цель ИФИБ и стратегия развития – это подготовка высококвалифицированных кадров на базе передовых исследований и разработок новых перспективных методов и материалов в области инженерно-физической биомедицины. Занятие лидерских позиций в биомедицинских технологиях XXI века и внедрение их в образовательный процесс, что отвечает решению практикоориентированной задачи мирового уровня – диагностике и терапии на клеточном уровне социально-значимых заболеваний человека.
Выпуск журнала
Аннотация
We report a classical molecular-dynamics simulation of models of silicon nanoparticles and bulk sili-con, in both the crystalline and the amorphous phase, to investigate their vibrational properties. By using a dynamical-matrix approach and a bond-polarizability model, together with a Raman-decomposition approach [Phys. Rev. B 100, 134309 (2019)], we present a comprehensive analysis of the vibrational spec-tra. In particular, the dependence of the high-frequency range of the Raman spectra on the nanoparticle size is studied. The results are in good agreement with Raman measurements on crystalline nanoparticles and explain the role of the nanoparticle surface, which is responsible for a shift in the Raman spectrum dependent on the particle size. In the low-frequency range, our Raman calculations reproduce well the Lamb-mode signatures, which obey the selection rules deduced by Duval [Phys. Rev. B 46, 5795 (1992)]. As a result of systematic Raman modeling, we confirm the scaling of the main signatures (ascribed to the Lamb modes with l = 0, 2) with respect to the nanoparticle size. By using the Raman-decomposition approach, we demonstrate that only a thin surface layer several angstroms in thickness contributes to the low-frequency Raman signature regardless of the nanoparticle size in the case of both the amorphous and the crystalline phase. Finally, we study the role of the coordination number of the atoms in the surface layer of a nanoparticle in order to explain the difference between the crystalline and amorphous vibrational spectra. The approach developed provides knowledge necessary for the correct interpretation of Raman spectra of nanoparticles, which opens up the possibility of quantitative control of surface-induced effects that may be relevant to various applications.
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Цитирование
Vibrational Analysis of Silicon Nanoparticles Using Simulation and Decomposition of Raman Spectra / Povarnitsyn, ME [et al.] // Physical Review Applied. - 2020. - 14. - № 1. - 10.1103/PhysRevApplied.14.014067
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