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

Abstract

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.

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

“…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.…”

Structure variation of intersubband electron–acoustic phonon scattering rate in coupled quantum wells

“…[5][6][7] At low temperature (TӶ77 K) when the subband energy separation ⌬E is smaller than the optic phonon energy ប LO , intersubband relaxation by optic phonons is quenched, thereby proceeding by slower scattering processes. 1-4 The operation of these ACQW structures critically depends on the electron lifetime in each energy level which, in turn, is strongly influenced by intersubband electron-phonon interaction.…”