Premium
Electron irradiation‐induced effects on optical spectra of (NH 4 ) 2 ZnCl 4 : x Sr 2+ single crystals
Author(s) -
Gaffar M. A.,
Abu ElFadl A.,
Bin Anooz S.
Publication year - 2003
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.200310010
Subject(s) - irradiation , analytical chemistry (journal) , absorption (acoustics) , band gap , chemistry , attenuation coefficient , absorption spectroscopy , atomic physics , materials science , optics , optoelectronics , physics , chromatography , nuclear physics , composite material
The effect of electron‐beam irradiation with different doses on optical constants of (NH 4 ) 2 ZnCl 4 : x Sr 2+ crystals with x=0.000, 0.020, 0.039, 0.087 or 0.144 wt% has been studied. The optical transmission in the energy range 3.4‐6.4 eV was measured hence the absorption coefficient was computed as a frequency function. The absorption coefficient was also calculated as a function of electron‐beam dose. Irradiation with e‐beam did not affect the allowed indirect type of transition responsible for interband transitions of (NH 4 ) 2 ZnCl 4 : x Sr 2+ crystals. Values of the optical energy gap E g and optical moment E p for electronic interband transition of unexposed and (NH 4 ) 2 ZnCl 4 : x Sr 2+ crystals after e‐beam exposure were deduced. The area under the absorption band at 5.30 eV was used to evaluate the effect of e‐irradiation on optical parameters of samples with x=0.00, 0.020 or 0.039. A shift in the position and a nonmonotonic change in the intensity of this band with increasing e‐beam dose was observed. Changes in the E g value were used to evaluate the effect of e‐beam exposure dose on (NH 4 ) 2 ZnCl 4 : x Sr 2+ samples with x=0.087 or 0.144. The obtained results were compared with those obtained for the same crystals after irradiation with different γ‐doses.