Reduction of electron-optical phonon scattering rates in a quantum well with a phonon wall

Photocurrent spectroscopy and study of subband parameters for heavy holes in nanoscale In 0.53 Ga 0.47 As/In 0.52 Al 0.48 As multiquantum well structuresThe anomalies in photoluminescence spectra of modulation doped AlGaAs/GaAs/AlGaAs double barrier heterostructures with various GaAs quantum well ͑QW͒ widths are observed. The intensity of the photoluminescence peak excited by Ar laser and associated with electron optical transitions from the second QW subband to the valence band becomes higher than for the case of the first ͑lowest͒ subband in the GaAs QW width range Lϭ22.5-30 nm. The calculations of electron-polar optical phonon scattering rate show that the well-width dependence of the intersubband electron scattering rate due to emission of confined and interface optical phonons is responsible for the photoexcited electron subband population redistribution and anomalies in the photoluminescence spectra. The transition rate for the second QW subband electron binding to the exciton state is evaluated as 25ϫ10 10 s Ϫ1 at LϽ22.5 nm and 4ϫ10 10 s Ϫ1 at 22.5ϽLр30 nm.

Section: Electron Scattering Rates By Confined and Interface Optimentioning

confidence: 99%

“…The electron scattering rate from subband i to subband f due to emission ͑absorption͒ of an optical phonon with the energy ប is given by [4][5][6][7][8] …”

Section: Electron Scattering Rates By Confined and Interface Optimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photoluminescence and electron subband population in modulation doped AlGaAs/GaAs/AlGaAs heterostructures

Požela

Jucienė

Namajūnas

et al. 1997

“…For that reason this double well structure has attracted much attention recently. [13][14][15][16][17][18] A few years ago, Zhu et al 19 studied the electron mobility in GaAs/AlAs multiple quantum wells fabricated by inserting several thin AlAs barrier layers into a GaAs/AlAs well. After comparing their results with those obtained in a single well, they claimed that the electron mobility is higher in the case of a multiple quantum well.…”

Section: Analysis Of the Scattering Of Electrons By Special Vibrationmentioning

confidence: 99%

Analysis of the scattering of electrons by special vibrational modes in a GaAs quantum well with a thin AlAs middle barrier: Mobility modulated by a transversal electric field

Wang

Lima

Troper

et al. 1999

Articles you may be interested inElectric field induced oscillating electron mobility in asymmetric wide GaAs/AlxGa1−xAs quantum well structure Electric field effects on electron mobility in n-AlGaAs/GaAs/AlGaAs single asymmetric quantum wells J.Effects of interface roughness and phonon scattering on intersubband absorption linewidth in a GaAs quantum well Appl. Phys. Lett. 78, 3448 (2001); 10.1063/1.1376154 Transport and quantum electron mobility in the modulation Si δ-doped pseudomorphic GaAs/In 0.2 Ga 0.8 As/Al 0.2 Ga 0.8 As quantum well grown by metalorganic vapor phase epitaxyThe scattering rates for the intra-and intersubband transitions of electrons in a GaAs/AlAs quantum well with a central AlAs thin layer assisted by the emission and absorption of optical phonon modes are calculated in the case where a transversal electric field is applied through the structure in order to modulate the electronic density inside the well. The role of the confined and interface phonon modes in reducing the electron mobility is analyzed separately to permit the identification of the effect of the transversal electric field on this mobility. The electron behavior indicates that electrons of different subbands can be separated in real space by the applied transversal electric field.

“…However, it provides more accurate results than the simplistic separatedsingle QW model, and becomes increasingly important to addressing recent issues on scattering time engineering for improving the transport and optical properties of quantum devices. 13,14 …”

Section: Introductionmentioning

confidence: 99%

Phonon dispersion and electron–polar optical phonon interaction in coupled quantum-well structures in the modified image–charge ansatz approach

Wang

Leburton

Požela³

1997

Phonon dispersion and Fröhlich interaction in coupled quantum-well structures are derived by using a modified image–charge ansatz that shows that the mode symmetry in the surface phonon dispersion of single quantum-well (QW) structures is modified by the addition of a thin inner barrier. The electron–phonon scattering rates are evaluated for phonons in the entire coupled QW configuration and compared with the corresponding rates calculated for phonons in the separated-single QW approximation. Our calculations show that the separated-single QW phonon model provides reasonable estimates of the electron–phonon scattering rates except for intersubband processes when the quantized energy separation between the initial and final electron states is in resonance with the polar optical phonon energy.