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Acoustic Phonon

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J.m. Gerard – One of the best experts on this subject based on the ideXlab platform.

  • Acoustic Phonon sidebands in the emission line of single InAs/GaAs quantum dots
    Physical Review B, 2003
    Co-Authors: Ivan Favero, Guillaume Cassabois, Robson Ferreira, David Darson, Christophe Voisin, Jérôme Tignon, Claude Delalande, G. Bastard, Ph. Roussignol, J.m. Gerard

    Abstract:

    We present an experimental and theoretical study of the existence of Acoustic Phonon sidebands in the emission line of single self-assembled InAs/GaAs quantum dots. Temperature-dependent photoluminescence measurements reveal a deviation from a Lorentzian profile with the appearance of lateral sidebands. We obtain an excellent agreement with calculations done in the framework of the Huang-Rhys formalism. We conclude that the only relevant parameter for the observation of Acoustic Phonon sidebands is the linewidth of the central zero-Phonon line. At high temperature, the quasi-Lorentzian quantum dot line appears to be fully determined by the Acoustic Phonon sidebands.

  • Acoustic Phonon sidebands in the emission line of single inas gaas quantum dots
    Physical Review B, 2003
    Co-Authors: Ivan Favero, Guillaume Cassabois, Robson Ferreira, David Darson, Christophe Voisin, Jérôme Tignon, Claude Delalande, G. Bastard, Ph. Roussignol, J.m. Gerard

    Abstract:

    We present an experimental and theoretical study of the existence of Acoustic Phonon sidebands in the emission line of single self-assembled InAs/GaAs quantum dots. Temperature-dependent photoluminescence measurements reveal a deviation from a Lorentzian profile with the appearance of lateral sidebands. We obtain an excellent agreement with calculations done in the framework of the Huang-Rhys formalism. We conclude that the only relevant parameter for the observation of Acoustic Phonon sidebands is the linewidth of the central zero-Phonon line. At high temperature, the quasi-Lorentzian quantum dot line appears to be fully determined by the Acoustic Phonon sidebands.

  • Efficient Acoustic Phonon broadening in single self-assembled InAs/GaAs quantum dots
    Physical Review B: Condensed Matter and Materials Physics, 2002
    Co-Authors: Claire Kammerer, A. Lemaitre, Guillaume Cassabois, Christophe Voisin, Claude Delalande, Ph. Roussignol, J.m. Gerard

    Abstract:

    We report systematic temperature-dependent measurements of photoluminescence excitation spectra in single self-assembled InAs/GaAs quantum dots. We studied the increase with temperature of the excited-state homogeneous linewidth for different quantum dots. We found a correlation between the Acoustic Phonon broadening efficiency and the background intensity in the photoluminescence excitation spectra. These results demonstrate the interaction of the discrete quantum dot excited states with a quasicontinuum of states and impose severe limitations on the isolated artificial macroatom scheme for a single quantum dot.

Alexander A Balandin – One of the best experts on this subject based on the ideXlab platform.

  • Acoustic Phonon spectrum engineering in bulk crystals via incorporation of dopant atoms
    Applied Physics Letters, 2018
    Co-Authors: Fariborz Kargar, Elias H Penilla, Ece Aytan, Jacob S Lewis, Javier E Garay, Alexander A Balandin

    Abstract:

    We report results of Brillouin—Mandelstam spectroscopy of transparent Al2O3 crystals with Nd dopants. The ionic radius and atomic mass of Nd atoms are distinctively different from those of the host Al atoms. Our results show that even a small concentration of Nd atoms incorporated into the Al2O3 samples produces a profound change in the Acoustic Phonon spectrum. The velocity of the transverse Acoustic Phonons decreases by ∼600 m/s at the Nd density of only ∼0.1%. Interestingly, the decrease in the Phonon frequency and velocity with the doping concentration is non-monotonic. The obtained results, demonstrating that modification of the Acoustic Phonon spectrum can be achieved not only by traditional nanostructuring but also by low-concentration doping, have important implications for thermal management as well as thermoelectric and optoelectronic devices.

  • direct observation of confined Acoustic Phonon polarization branches in free standing semiconductor nanowires
    Nature Communications, 2016
    Co-Authors: Fariborz Kargar, Bishwajit Debnath, J P Kakko, Antti Saynatjoki, Harri Lipsanen, Denis L Nika, Roger K Lake, Alexander A Balandin

    Abstract:

    Similar to electron waves, the Phonon states in semiconductors can undergo changes induced by external boundaries. However, despite strong scientific and practical importance, conclusive experimental evidence of confined Acoustic Phonon polarization branches in individual free-standing nanostructures is lacking. Here we report results of Brillouin-Mandelstam light scattering spectroscopy, which reveal multiple (up to ten) confined Acoustic Phonon polarization branches in GaAs nanowires with a diameter as large as 128 nm, at a length scale that exceeds the grey Phonon mean-free path in this material by almost an order-of-magnitude. The dispersion modification and energy scaling with diameter in individual nanowires are in excellent agreement with theory. The Phonon confinement effects result in a decrease in the Phonon group velocity along the nanowire axis and changes in the Phonon density of states. The obtained results can lead to more efficient nanoscale control of Acoustic Phonons, with benefits for nanoelectronic, thermoelectric and spintronic devices.

  • Direct observation of confined Acoustic Phonon polarization branches in free-standing semiconductor nanowires
    Nature Communications, 2016
    Co-Authors: Fariborz Kargar, Bishwajit Debnath, J P Kakko, Antti Saynatjoki, Harri Lipsanen, Denis L Nika, Roger K Lake, Alexander A Balandin

    Abstract:

    Similar to electron waves, the Phonon states in semiconductors can undergo changes induced by external boundaries. However, despite strong scientific and practical importance, conclusive experimental evidence of confined Acoustic Phonon polarization branches in individual free-standing nanostructures is lacking. Here we report results of Brillouin—Mandelstam light scattering spectroscopy, which reveal multiple (up to ten) confined Acoustic Phonon polarization branches in GaAs nanowires with a diameter as large as 128 nm, at a length scale that exceeds the grey Phonon mean-free path in this material by almost an order-of-magnitude. The dispersion modification and energy scaling with diameter in individual nanowires are in excellent agreement with theory. The Phonon confinement effects result in a decrease in the Phonon group velocity along the nanowire axis and changes in the Phonon density of states. The obtained results can lead to more efficient nanoscale control of Acoustic Phonons, with benefits for nanoelectronic, thermoelectric and spintronic devices. In nanostructures, Phonon confinement could lead to better control of Phonon-electron coupling and thermal properties. Here, the authors use light scattering spectroscopy to measure Acoustic Phonons confinement in individual free-standing nanowires, their energy dispersion and energy scaling.

Guillaume Cassabois – One of the best experts on this subject based on the ideXlab platform.

  • Acoustic Phonon sidebands in the emission line of single InAs/GaAs quantum dots
    Physical Review B, 2003
    Co-Authors: Ivan Favero, Guillaume Cassabois, Robson Ferreira, David Darson, Christophe Voisin, Jérôme Tignon, Claude Delalande, G. Bastard, Ph. Roussignol, J.m. Gerard

    Abstract:

    We present an experimental and theoretical study of the existence of Acoustic Phonon sidebands in the emission line of single self-assembled InAs/GaAs quantum dots. Temperature-dependent photoluminescence measurements reveal a deviation from a Lorentzian profile with the appearance of lateral sidebands. We obtain an excellent agreement with calculations done in the framework of the Huang-Rhys formalism. We conclude that the only relevant parameter for the observation of Acoustic Phonon sidebands is the linewidth of the central zero-Phonon line. At high temperature, the quasi-Lorentzian quantum dot line appears to be fully determined by the Acoustic Phonon sidebands.

  • Acoustic Phonon sidebands in the emission line of single inas gaas quantum dots
    Physical Review B, 2003
    Co-Authors: Ivan Favero, Guillaume Cassabois, Robson Ferreira, David Darson, Christophe Voisin, Jérôme Tignon, Claude Delalande, G. Bastard, Ph. Roussignol, J.m. Gerard

    Abstract:

    We present an experimental and theoretical study of the existence of Acoustic Phonon sidebands in the emission line of single self-assembled InAs/GaAs quantum dots. Temperature-dependent photoluminescence measurements reveal a deviation from a Lorentzian profile with the appearance of lateral sidebands. We obtain an excellent agreement with calculations done in the framework of the Huang-Rhys formalism. We conclude that the only relevant parameter for the observation of Acoustic Phonon sidebands is the linewidth of the central zero-Phonon line. At high temperature, the quasi-Lorentzian quantum dot line appears to be fully determined by the Acoustic Phonon sidebands.

  • Efficient Acoustic Phonon broadening in single self-assembled InAs/GaAs quantum dots
    Physical Review B: Condensed Matter and Materials Physics, 2002
    Co-Authors: Claire Kammerer, A. Lemaitre, Guillaume Cassabois, Christophe Voisin, Claude Delalande, Ph. Roussignol, J.m. Gerard

    Abstract:

    We report systematic temperature-dependent measurements of photoluminescence excitation spectra in single self-assembled InAs/GaAs quantum dots. We studied the increase with temperature of the excited-state homogeneous linewidth for different quantum dots. We found a correlation between the Acoustic Phonon broadening efficiency and the background intensity in the photoluminescence excitation spectra. These results demonstrate the interaction of the discrete quantum dot excited states with a quasicontinuum of states and impose severe limitations on the isolated artificial macroatom scheme for a single quantum dot.