Structure and Optical Properties for Lead Chalcoganides

Lead Chalcoganides thin films ( PbTe , PbSe, PbS) have been prepared by thermal evaporation method ,with 0،35 mm thickness , This thin films that deposited on glass and wafer (Si) substrate at room temperature (303º K) , this films was annealed to temperatures ( Ta=373 º K ,473 º K) for one hour. X-Ray diffraction technique ware used to study the structure of these films and the effect of annealing on it . X-ray diffraction analysis confirmed that these films are polycrystalline having cubic structure cell and lattice parameters are reported . From the absorption spectrum the optical energy gap for (PbTe,PbSe,PbS) thin films has been determined in the strong absorption region . The relationship between the optical gap of lead Chalcoganides and annealing temperature have been reported and discussed.