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Inhomogeneous Broadening (inhomogeneous + broadening)
Selected AbstractsTransient Optical Studies of Interfacial Energetic Disorder at Nanostructured Dye-Sensitised Inorganic/Organic Semiconductor HeterojunctionsCHEMPHYSCHEM, Issue 1 2003Saif A. Haque Dr. Broadening needs energy: Hole-transfer reactions at a dye-sensitised nanocrystalline TiO2/organic hole-conductor (HTM) interface are mainly driven by the free energy difference ,G(dye-HTM). Inhomogeneous broadening of ,G(dye-HTM) controls the yield of this interfacial charge-transfer reaction (see picture, curve b) and is therefore an important limitation on the voltage output of photovoltaic devices based upon such interfaces. [source] Raman scattering of acoustical modes of silicon nanoparticles embedded in silica matrix,JOURNAL OF RAMAN SPECTROSCOPY, Issue 1-3 2006M. Ivanda Abstract The Raman scattering from acoustical phonons of silicon quantum dots in glass matrix was investigated. Two peaks that correspond to symmetric and quadrupolar spheroidal vibrations were found. A model calculation for in- and off-resonance scattering conditions was used, which considered the homogeneous broadening due to interaction with matrix and the inhomogeneous broadening due to particle size distribution. A strong dependence of the light-to-vibration coupling coefficient on the particles size was needed for fitting the Raman data. This result suggests that resonance with electronic transitions of the silicon nanoparticles is important for excitation at 514.5 nm. The size distribution obtained from the Raman data is in agreement with the results of high-resolution transmission electron microscopy. Copyright © 2006 John Wiley & Sons, Ltd. [source] Effect of Sc Substitution for Al on the Optical Properties of Transparent Ce:YSAG CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2008Tao Feng Transparent Ce:YAG (Ce:Y3Al5O12) and Ce:YSAG (Ce:Y3ScxAl5,xO12) ceramics have been successfully fabricated using Sc3+ to substitute for Al3+ in Ce:YAG. The effect of Sc substitution on the luminescent properties of Ce:YAG has been investigated. At the substitution level of 20 at.% of Sc3+ for Al3+, the emission intensity of Ce:YSAG is the highest. Meanwhile, the doping of Sc into Ce:YAG lattice broadened both the absorption and emission bands, which is believed to be due to the inhomogeneous broadening of the 5d energy level of Ce3+ caused by the Sc3+ substitution. [source] Homogeneous and inhomogeneous linewidth broadening of single polar GaN/AlN quantum dotsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009F. Demangeot Abstract We report on the dependence on temperature of the homogeneous and inhomogeneous broadening of the fundamental transition of single polar GaN/AlN quantum dots (QDs). Stranski-Krastanov QDs have been grown by molecular beam epitaxy using NH3 as a nitrogen source, with a very low surface density. Low temperature (LT) microphotoluminescence measurements have been performed on 200 nm wide mesas in order to isolate the luminescence of single QDs. The linewidth is found to vary from 590 ,eV at 4 K up to 1350 ,eV at 65 K in a dot of 6 monolayer height. Though the LT linewidth is still dominated by spectral diffusion, the temperature dependent broadening up to 50 K is mainly accounted for by interactions between excitons and acoustic phonons through a coupling coefficient value nearly two orders of magnitude larger than its counterpart in InAs QDs. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Giant reflectance anisotropy of polar cubic semiconductors in the far infraredPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2003Yu. A. Kosevich Abstract We present our measurements and model for the reflectancre anisotropy of the (001) surface of polar cubic zinc-blende semiconductor in the far infrared. We observe that the relative reflectance difference of GaAs(001) in the far infrared can reach the value of twenty percents which is two orders of magnitude higher than the reflectance difference of the GaAs(001) in the near-ultraviolet - visible range. The most strong reflectance anisotropy was observed in the optical phonon Reststrahlbande and its vicinity. We relate the observed reflectance anisotropy with the anisotropy of the optical-phonon and plasma damping constants. Such anisotropy can be caused by anisotropic inhomogeneous broadening of the frequencies of the optical-phonon and plasma oscillations polarized respectively along the [110] and directions. This effect can be understood in terms of the lattice-deformation-induced changes of the optical-phonon force constants and electron-effective-mass tensor components. Anisotropic inhomogeneous strain of the lattice can in turn be induced by anisotropic microscopic short-range ordering of point defects (dopants) and dislocations in near-surface regions of noncentrosymmentric zinc-blende semiconductors. The observed giant reflectance anisotropy can be used as a sensitive tool for the far infrared characterization of zinc-blende semiconductors. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High quality InAs quantum dots covered by InGaAs/GaAs hetero-capping layerPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2003R. Ohtsubo Abstract Self-assembled InAs quantum dots with high performance were fabricated by molecular beam epitaxy via Stranski,Krastanov growth mode and InGaAs/GaAs hetero-capping growth. The size and shape of the dots were modified during the first GaAs capping layer, which plays an important role of a reduction in the inhomogeneous broadening. In particular, when the substrate temperature of the GaAs capping layer was 450,°C, the PL linewidth decreased to less than 20,meV. In order to reduce the residual strain in the InAs QDs and the capping layer, the InGaAs capping layer was additionally grown on the InAs dots covered by the first GaAs capping layer. As a result, the presented InGaAs/GaAs hetero-capping layer induced strong photoluminescence (PL) intensity, narrow PL linewidth and 1.3,,m light emission at room temperature. [source] | ||||||||||