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The characteristical asymmetric shapes of the Raman lines caused by the collective plasmon–LO phonon excitations in heavily doped GaAs/AlAs superlattices were analyzed in order to separate the influence of the magnetic field on the spatial extent of the collective excitations and on their damping constant, which is attributed to the AC conductivity. It was shown that the magnetic field influences the damping of the plasmon-like excitations stronger than their spatial extent.

The photoluminescence of electron excitations was measured in differently oriented InAs self-assembled quantum dot systems. The spin–orbit-split excitons were observed in resonant photoluminescence when the excitation energy was close to the exciton energy while the off-resonant photoluminescence spectra reveal the heavy-hole excitons. The sizes of quantum dots were obtained by the fitting of the calculated excitation energies to those measured in experiment.

The interaction between electron excitations and LO phonons is studied by Raman scattering inδ-doping GaAs superlattices. The Raman spectra measured close to the E0+Δ0resonance of GaAs present Fano-like coupling of the LO phonons with the quasicontinuum single-particle electron excitations. Due to the self-consistent origin of the electron-energy spectrum in δ-doping superlattices the resonance of the Fano interference was found to be strongly dependent on the electron density as well as the excitation energy.