相关论文: On the Raman shift in nanosized crystals
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…
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…
A method of statistical description of thermodynamic properties of nanocrystals is developed. It is established that size-dependent quantization of vibrational modes results in formation of excess pressure of the phonon gas acting outwards…
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…
A comparative analysis of two Raman line-shape functions has been carried out to validate the true representation of experimentally observed Raman scattering data for semiconducting nanomaterials. A modified form of already existing phonon…
A phonon frequency shift of the radial breathing mode for metallic single wall carbon nanotubes is predicted as a function of Fermi energy. Armchair nanotubes do not show any frequency shift while zigzag nanotubes exhibit phonon softening,…
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…
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…
We report a combined electron transmission and Raman spectroscopy study of InAs nanowires. We demonstrate that the temperature dependent behavior of optical phonon energies can be used to determine the relative wurtzite fraction in the InAs…
In crystalline nanoparticles the Raman peak is downshifted with respect to the bulk material and has asymmetric broadening. These effects are straightly related to the finite size of nanoparticles, giving the perspective to use the Raman…
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…
In the present paper, we utilize the coupled-oscillator model describing the hybridization of optical phonons in touching and/or overlapping particles in order to study the Raman spectra of nanoparticles organized into various types of…
We study the dynamic electronic polarizability of a single nano-scale spherical metallic grain using quantum mechanical approach. We introduce the model for interacting electrons bound in the grain allowing us numerically to calculate the…
New approach on interpretation and processing of Raman spectra of complex perovskites is suggested. Raman spectra of $PbMg_{1/3}Nb_{2/3}O_{3}$ and $% PbSc_{1/2}Ta_{1/2}O_{3}$ are successfully described on the basis of the phonon-confinement…
Titanium dioxide (TiO2) nanocrystals were prepared by wet chemical method and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Raman scattering (RS) and photoluminescence (PL). The X-ray diffraction shows…
We measure the temperature dependence of the Raman spectra of metallic and semiconducting nanotubes. We show that the different trend in metallic tubes is due to phonon re-normalization induced by the variation in electronic temperature,…
In this letter, we propose a new model that explains the Raman peak downshift observed in nanoparticles with respect to bulk materials. The proposed model takes into account discreteness of the vibrational spectra of nanoparticles. For…
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…
Based on the fact that both hardness and vibrational Raman spectrum depend on the intrinsic property of chemical bonds, we propose a new theoretical model for predicting hardness of a covalent crystal. The quantitative relationship between…
We present a theoretical model to describe the double-resonant scattering process in arbitrary carbon nanotubes. We use this approach to investigate the defect-induced $D$ mode in CNTs and unravel the dependence of the $D$-mode frequency on…