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Amorphous Cd-doped GeS2 films were prepared by thermal evaporation. In the Raman spectra of GeS2:Cd films with nominal Cd content above 8% at high laser power densities (above 200 kW/cm2), Raman peaks of the CdS LO and 2LO phonons are observed as evidence for the formation of CdS nanocrystals in the films under laser irradiation. The nanocrystals are formed due to the photoenhanced diffusion of atoms in the GeS2:Cd films, which is caused by non-thermal photofluidity (a drastic decrease of the film viscosity under illumination) that enables the aggregation of Cd and S atoms in nanocrystals. Factors responsible for the variation of the CdS LO phonon peak as a function of laser power density are discussed.

Zn-doped As2Se3 and As2S3 films were prepared by thermal evaporation. Their amorphous structure was confirmed by Raman spectroscopy. Zinc chalcogenide nanocrystals can be formed in the films under laser irradiation due to the photoenhanced diffusion of atoms in the arsenic chalcogenide films, which enables aggregation of Zn and S(Se) atoms in nanocrystals. For As2S3:Zn films, not only ZnS, but also ZnO crystallites can be formed under irradiation with UV laser light due to oxidation of the film surface with abundant zinc atoms.

Yu.M. Azhniuk is grateful to Deutscher Akademischer Austauschdienst (DAAD) for the support of his research at Chemnitz University of Technology.

Amorphous Zn-doped As2Se3 films with a nominal zinc content x up to 10 at.% were prepared by thermal evaporation. Their structure is characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoemission spectroscopy (XPS), and Raman spectroscopy. The AFM data show a considerable increase of the film surface roughness for films with x > 5 at.%. A strong gradient of the Zn content decreasing into the film depth is confirmed by the EDX and XPS data. Heavily Zn-doped (above 7 at.%) As2Se3 films reveal photostructural changes in the course of the Raman measurements. New Raman features are attributed to TO and LO vibrations of ZnSe nanocrystallites formed in the film under laser illumination. Depending on the laser wavelength and power density, the ZnSe nanocrystallites can experience tensile strain in the film due to a non-thermal photoplastic effect in the As2Se3 film resulting in a partial removal of the material from the laser spot. The tensile strain value, estimated from the TO and LO phonon frequency shift, is shown to reach up to 2.9 GPa.

The unpolarized Raman spectra of TlIn(S0.95Se0.05)2 single crystals in the frequency interval 16–340 cm−1 are studied in the temperature interval 30 ≤ T ≤ 293 K. The Raman spectra are analyzed by a multipeak simulation using Lorentzian contours. The temperature behavior of the vibrational band parameters (half-width, intensity, and frequency) is studied with the emphasis on the temperature range, where changes related to phase transformations are revealed.

Real and imaginary parts of the dielectric function of TlInS2 single crystals in the spectral range from 1 to 5 eV were determined within a temperature range of 133–293 K from spectroscopic ellipsometry measurements. The energies of interband transitions (critical points) for TlInS2 were obtained from the second derivatives of the dielectric function. Temperature dependent features observed in the temperature range of the structural phase transition (190–220 K) and at lower temperatures are discussed. Дійсну та уявну частини діелектричної функції кристалу TlInS2 визначено в спектральному діапазоні від 1 до 5 еВ в інтервалі температур 133-293 К із спектроскопічних еліпсометричних досліджень. Енергії міжзонних переходів (критичних точок) отримано для TlInS2 з других похідних від діелектричних функцій. Обговорюються особливості в області структурних фазових переходів (190-220 К) та при нижчих температурах. Из спектроскопических эллипсометрических исследований определена действительная и мнимая части диэлектрической функции кристалла TlInS2 в спектральном диапазоне от 1 до 5 эВ в интервале температур 133–293 К. Энергии между зонных переходов (критических точек) получено для TlInS2 из вторых производных от диэлектрических функций. Обсуждаются особенности в области структурных фазовых превращений (190–220 К) и при меньших температурах.

A series of samples with quaternary CdS1−x−ySexTey nanocrystals with cations of three types distributed over nanocrystal lattice sites were grown in a borosilicate glass matrix by the diffusion-limited growth technique. Their Raman spectra confirm the three-mode compositional behaviour of CdS1−x−ySexTey phonon spectra. The compositional dependence of the LO phonon frequencies is analysed experimentally for a series of samples containing nanocrystals with x≈y.