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Raman spectra of CulnSwSe(l-,, mixed crystals are reponed. The dependence of the mode frequencies on lhe composition is studied. Two-mode behaviour is observed for the higherfrequency phonons. One-mode behaviour is found for the low-frequency modes corresponding to the zone-edge acoustic phonons of zincblende.Solid solutions of CuInSbSez(l-z) type are considered as an alternative for CuInSe;? as an absorber in thin-film solar cells [l]. They crystallize in the chalcopyrite structure over the whole composition range. The band gap varies from 1.04 eV for CuInSe;? to 1.53 eV for CuInSz. To our knowledge no data on the lattice dynamics of this system have been

The x-ray absorption near edge structure (XANES) of selenium is investigated in the crystals with compositions from the pseudobinary cut line Cu2Se-In2Se3. This includes CuInSe2, indium-rich ternary compounds (Cu2In4Se7, CuIn3Se5, CuIn5Se8, CuIn7Se11) and α-In2Se3. The absorption at the K and L3/L2 edges of selenium has been measured using synchrotron radiation. Two theoretical approaches are used to the interpretation of the experimental data: the band structure calculation and the real-space multiple-scattering (RSMS) method. In the first one, the angular momentum projected densities of states at Se sites are calculated for CuInSe2 and α-In2Se3 for the energies up to 17 eV above the conduction band minimum by the LMTO-ASA method. The RSMS approach represented by the FEFF8 code is used to calculate the XANES spectra for the phases with tetragonal symmetry. Clusters up to 160 atoms are used in the calculations. The influence of different structural factors on the selenium XANES is studied.

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The new semiconductor materials (CuAlSe 2 ) x (2ZnSe) 1−x and (CuGaSe 2 ) x (2ZnSe) 1−x are grown by the chemical transport method over all the compositional range. Raman spectra of the mixed crystals are measured at room temperature. Order-disorder phase transitions from chalcopyrite to disordered zincblende structure are observed in both materials. Phonon modes are identified on the basis of the phonon assignments of the end components. Some new bands assigned as vibrational modes of the CuSe and AlSe complexes in ZnSe are found.

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