Enhancement of electron-phonon interaction in ultrashort-period GaAs/AlAs superlattices

Abstract

The interaction of electrons and phonons is strongly enhanced in ultrashort-period GaAs/AlAs superlattices. The enhancement is caused by an increase of the exciton binding energy with decreasing superlattice period. The photoluminescence spectra of indirect-gap superlattices exhibit a zero-phonon line due to scattering by defects and/or interfacial roughness as well as pronounced phonon sidebands. ͓S0163-1829͑97͒07015-X͔

Dispersion and Modulation of the Linear Optical Properties of GaAs–AlAs Superlattice Waveguides Using Quantum-Well Intermixing

“…It is worth noting that the large 169-meV blue-shift achieved in the present work was at a much lower temperature 750 C compared to the 900 C and 800 C used to achieve shifts of 140 [23] and 100 meV [22], respectively. The 47-meV energy detuning between the main superlattice peak and the small peak on the low energy side in the sample is in excellent agreement with longitudinal optical (LO) phonon energies in the AlAs layers [24], [25]. The large decrease in photoluminescence intensity upon disordering is partially attributed to the nature of the superlattice structure investigated to undergo a transition from a direct-to indirect-gap upon disordering.…”

Elementary energy bands in the band structure of AIV, AIIIBV crystals and superlattices built upon them

“…The energetic position of the conduction band at the Γ-and Z-points is the same within the numerical accuracy. Therefore, these results do not determine whether the superlattice is an indirect one, which univocally follows from experimental data [30]. We obtained analogous results in the ab-initio band-structure calculations of the 10 10 (GaAs) (AlAs) / superlattice.…”

“…Figure 1 presents the band structure of 5 5 (GaAs) (AlAs) / superlattice calculated by the ABINIT code. The smallest forbidden energy gap is located in the Γ-Z direction and equals ~1 eV that is essentially eV [30]. The energetic position of the conduction band at the Γ-and Z-points is the same within the numerical accuracy.…”

Universality of the Empty-Lattice Approximation to Predict the Topology of Energy Spectra of High-Symmetry Crystals and Superlattices Based upon Them

“…The band structure calculation results show also that the smallest forbidden energy gap is located in the Γ − Z direction and equals ∼ 1 eV which is essentially less than the experimental value 1.9407 eV [17]. The valence band of (GaAs) 5 /(AlAs) 5 is composed of 4 groups of minibands.…”