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Crystal Research and Technology |
Cryst. Res. Technol. 41, 487 (2006) - Abstract -
Optical properties of pure and metal ions doped ammonium sulfate single crystals
A. Abu El-Fadl and S. Bin Anooz*
Physics Department, Faculty of Science, Assiut University, 71516 Assiut, Egypt
*Physics Department, Faculty of Science, Hadhramout University of Science and Technology, 50511 Mukalla, Republic of Yemen
A study of the optical properties of pure-and some metal ions doped ammonium sulfate crystals (AS) were made. Optical constants of AS crystals were calculated at room temperature. The optical absorption coefficient was analyzed and interpreted to be in the allowed direct transition. The introduction of Rb+ or Cs+ ions gives rise to an intense charge transfer band with a maximum at λ = 310 nm in the optical spectrum. In case of Cr3+ -doping, the absorption shows a shoulder just before the onset band to band transition. The values of the allowed direct energy gap Eg for undoped and doped crystals were calculated. It was found that Eg values were decreased with metal ions doping. The refractive index, the extinction coefficient and both the real and imaginary parts of the dielectric permittivity were calculated as a function of photon energy. The validity of Cauchy-Sellimeier equation was checked in the wavelength range 4.9 - 5.6 eV and its parameters were calculated.
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