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A step-by-step evolution of an asymmetric Raman line-shape function from a Lorentzian line-shape is presented here for low dimensional semiconductors. The evolution reported here is based on the phonon confinement model which is…

介观与纳米尺度物理 · 物理学 2016-09-01 Rajesh Kumar , Gayatri Sahu , Shailendra K. Saxena , Hari M. Rai , Pankaj R. Sagdeo

A modified phonon confinement model considering the size distribution, an improved phonon dispersion curve and a confinement function is developed for the calculation of size dependent Raman spectra of the silicon (Si) nanocrystals. The…

介观与纳米尺度物理 · 物理学 2015-05-13 Sanjeev K. Gupta , Prafulla K. Jha

A comparison of experimentally observed Raman scattering data with Raman line-shapes, generated theoretically using phonon confinement model, has been carried out to understand the sensitivity of different Raman spectral parameters on…

介观与纳米尺度物理 · 物理学 2020-03-20 Neeshu K. M. , Chanchal Rani , Ritika Kaushik , Manushree Tanwar , Ashisha Kumar , Rajesh Kumar

Confined acoustic and optical phonons in Si nanoclusters embedded in sapphire, synthesized using ion-beam implantation are investigated using Raman spectroscopy. The l = 0 and l = 2 confined acoustic phonons, found at low Raman shift, are…

材料科学 · 物理学 2008-09-10 Satyaprakash Sahoo , S. Dhara , S. Mahadevan , A. K. Arora

Theoretical Raman line shape functions have been studied to take care of quantum confinement effect and Fano effect individually and jointly. The characteristics of various Raman line shapes have been studied in terms of the broadening and…

Raman spectra from silicon nanostructures, recorded using excitation laser power density of 1.0 kW/cm^2, is employed here to reveal the dominance of thermal effects at temperatures higher than the room temperature. Room temperature Raman…

介观与纳米尺度物理 · 物理学 2012-01-25 Rajesh Kumar , Vivek Kumar , A. K. Shukla

Raman spectroscopy of crystalline/molecular systems is well backed with quantum chemical calculations and group theory, making it a unique characterization tool. For the "intermediate" case of nanoscale systems, however, the use of Raman…

化学物理 · 物理学 2017-04-07 Vitaly I. Korepanov , Hiro-o Hamaguchi

The observation of pure phonon confinement effect in germanium nanowires is limited due to the illumination sensitivity of Raman spectra. In this paper we measured Raman spectra for different size germanium nanowires with different…

量子物理 · 物理学 2009-11-13 Xi Wang , Ali Shakouri , Bin Yu , Xuhui Sun , Meyya Meyyappan

Revealing hidden non-radiative (dark) of resonant nanostructures using optical methods such as dark-field spectroscopy often becomes a sophisticated problem due to a weak coupling of these modes with a far-field radiation, whereas methods…

Extending the idea of optical microcavities to sound waves, we propose a {\it phonon cavity} consisting of two semiconductor superlattices enclosing a spacer with thickness determined by the acoustic wavelength at the center of the first…

凝聚态物理 · 物理学 2009-11-07 M. Trigo , A. Bruchhausen , A. Fainstein , B. Jusserand , V. Thierry-Mieg

Intermediate frequency range (511 - 514 cm-1) Si phonons in Si-SiO2 nanocomposites are shown to have contribution from both core1 and surface/interface1 Si phonons, where, ratio of contribution of the two depends on the size of a Si…

介观与纳米尺度物理 · 物理学 2015-03-13 Ekta Rani , Alka Ingale , A. Chaturvedi , M. P. Joshi , L. M. Kukreja

For nanoscale systems such as nanoparticles and 3D-bonded networks, the range of spatial coherence is well reflected in the Raman spectral pattern. For confined, or localized, phonons, the range of q-points contributing to the spectrum…

化学物理 · 物理学 2019-10-22 Vitaly I. Korepanov

Microscopic description of Raman spectra in nanopowders of nonpolar crystals is accomplished by developing the theory of disorder-induced broadening of optical vibrational eigenmodes. Analytical treatment of this problem is performed, and…

介观与纳米尺度物理 · 物理学 2020-11-25 Oleg I. Utesov , Andrey G. Yashenkin , Sergei V. Koniakhin

Strong light-matter coupling gives rise to polaritons -- quasiparticles that combine both photonic and material characteristics. Here, we show that polar nanocrystals exhibit structure- and environment-dependent Raman scattering, enabled by…

We present Raman spectroscopy of the polycrystalline Si and Ge films deposited by molecular beam deposition on a dielectric substrate. The Raman study has been made using lasers with different wavelengths. Structural properties of the…

An analytical form of the Raman shift dependence on size of nanocrystals is presented. Based on the hard confinement model, it works in those cases where the average phonon curve shows a quadratic dependence on the phonon quasi-momentum in…

其他凝聚态物理 · 物理学 2008-03-13 M. Salis , P. C. Ricci , A. Anedda

We calculate low-frequency Raman scattering from the confined acoustic phonon modes of CdS1-xSex nanoparticles embedded in borosilicate glass. The calculation of the Raman scattering by acoustic phonons in nanoparticles has been performed…

介观与纳米尺度物理 · 物理学 2009-04-16 Sanjeev K. Gupta , Prafulla K. Jha , Satyaprakash Sahoo , A. K. Arora , Y. M. Azhniuk

This work presents how first-principles simulations validated through experimental measurements lead to a new accurate prediction of the expected Raman shift as a function of strain in silicon. Structural relaxation of a strained primitive…

应用物理 · 物理学 2023-01-31 Nicolas Roisin , Marie-Stéphane Colla , Jean-Pierre Raskin , Denis Flandre

The temperature dependence below $T_{c}$ of the lineshape of optical phonons of different symmetry as seen in Raman scattering is investigated for superconductors with anisotropic energy gaps. It is shown that the symmetry of the…

凝聚态物理 · 物理学 2009-10-22 T. P. Devereaux

As the silicon industry continues to push the limits of device dimensions, tools such as Raman spectroscopy are ideal to analyze and characterize the doped silicon channels. The effect of inter-valence band transitions on the zone center…

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