Structural Parameters and Optical Properties of TlAlSe2 Compound

Horizontal directional freezing as a method used to get of study high purity TlAlSe from melt of initial components to obtain polycrystalline ingots with large grain size. Measurements of the crystal lattice parameters for the powder and thin films which obtain from X-ray diffraction technique showed that the value of the lattice parameters are a=4،254 Å c=8،50 Å. Thin films of TlAlSe2 were deposited on glass substrate by thermal evaporation in vacuum have polycrystalline structure. Optical parameters were calculated by study optical properties transmission and reflectivity. The optical absorption coefficient of TlAlSe2 solid solution has been studied. A direct allowed transition is 2،65 eV, and indirect allowed transition is 1،58 eV, and assisting phonon to 0،026 eV is also observed.