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The luminescence method has been employed for the first time to detect nonequilibrium phonons in CdTe quantum wells with Cd0.6Mn0.4Te barriers. The method makes use of the giant Zeeman splitting of exciton states in CdTe/(Cd,Mn)Te quantum wells and is promising for application in high-sensitivity subterahertz phonon spectrometry. The method can also be useful in revealing the spin-phonon coupling mechanisms in diluted magnetic semiconductors.

An experimental and theoretical study of the magnetic polaron states of two-dimensional excitons in quantum wells based on semimagnetic semiconductors (Cd,Mn)Te is reported. It is shown that magnetic-polaron formation in in-plane magnetic fields leads to a lowering of the system symmetry, provided the fields are not too strong. The magnetic moment of the polaron thus formed is not parallel to the external magnetic field and contains a component normal to the quantum-well plane. This spontaneous lowering of the symmetry results in a change of the polarization characteristics of the luminescence from magnetic polaron states and in a weakening (compared to the three-dimensional case) in the efficiency of magnetic field-induced polaron suppression.

Theory of specular light reflection from long-period quantum-well structures taking into account the exciton contribution to dielectric polarization has been developed for an arbitrary relation between the background refractive index in the well, n a, and barrier-material refractive index nb. General expressions for the optical reflection and transmission coefficients for a structure with N equidistant quantum wells are derived with the use of the Green’s function and transfer matrix methods. Normal and oblique light reflectance spectra from II-VI-based heterostructures were found to reveal a bright interference pattern caused by the difference between n a and n b. A comparison of the theory with experiment has yielded the dispersion of n a and n b within a broad wavelength range and the parameters of the quasi-two-dimensional heavyhole exciton (e1-hh1), namely, the resonant frequency and the radiative and nonradiative damping rates. Reflectance spectra from resonant Bragg and quasi-Bragg structures with real exciton parameters are calculated, and the effect on these spectra of the refractive-index difference and the deviation from the Bragg condition is analyzed.

A giant blue shift (≈0.5 eV) and a large decrease in the emission time of a spectral band corresponding to radiative recombination of spatially separated electrons and holes are observed in ZnSe/BeTe superlattices at high laser excitation levels. On the basis of numerical calculations, the observed defects are attributed to band bending arising in type-II structures at high carrier density.

A method has been developed for recording and analyzing the differential magnetoreflection (magnetotransmission) spectra of semiconductor structures with quantum wells. The method was used to determine the exciton g-factor in semimagnetic CdTe/(Cd, Mn)Te heterostructures with quantum wells. In nonmagnetic structures with quantum wells containing a two-dimensional electron gas, the excitonic damping depends on the spin state of the exciton. This effect is explained by the exchange contribution to exciton-electron scattering.

The photoluminescence spectra of type-II ZnSe/BeTe superlattices are investigated. Giant linear polarization of the luminescence is observed with unpolarized excitation in the spatially indirect exciton region. The effect is interpreted in a model of the general optical anisotropy of heterostructures with no common atom at the interfaces.

A study of reflectance spectra from thin ZnSxSe1−x solid-solution layers in the region of excitonic resonances is reported. It has been found that an increase in sulfur concentration in the layers increases the inhomogeneous broadening of the quantized polariton lines. It has been established that the inhomogeneous line broadening in a reflectance spectrum depends on the magnitude of exciton-photon mixing; it is small in the long-wavelength region where the photon component of the polariton is large, and large at short wavelengths where the mechanical component dominates.

Results of an optical study of heterostructures based on new compounds, ZnSe/ZnMgSSe, are presented. The possibility of using these compounds to produce high-quality quantum-well structures having strong exciton features in optical spectra is demonstrated. An analysis of reflectance spectra has yielded the exciton parameters: the resonant frequency, oscillator strength, and exciton line damping. The exciton binding energies have been determined from magneto-optical spectra. The samples studied have a high structural perfection and small inhomogeneous width of the excitonic resonances.