The effect of cobalt-doping on some of the optical properties of glycine zinc sulfate (GZS) single crystal

• Published in: Physica. B, Condensed matter Vol. 405; no. 16; pp. 3421 - 3426
• Main Authors: Abu EL-Fadl, A., Abdulwahab, A.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-08-2010; Elsevier
• Subjects: Absorption spectra; Cobalt; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystals; Cut off wavelength; Exact sciences and technology; GZS crystal; Nonlinear optical materials; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical energy gab; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Phonons; Physics; Single crystals; Sulfates; Zinc; Nonlinear optical materials; Optical energy gab; GZS crystal; Cut off wavelength; TGS; Transparency; Doping; Optical transition; Absorption coefficients; Zinc compounds; Energy gap; Monocrystals; Crystal growth from solutions; Optical materials; Cobalt additions; Absorption spectra; Transparent material
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2010.05.016

Glycine zinc sulfate (GZS) single crystals, pure and doped with three different ratios of cobalt ions were synthesized and grown by the slow evaporation technique of aqueous solutions at 34
°C. Optically transparent single crystals with dimensions up to 2×1.5×1.2
cm
3 were obtained in about four weeks. The optical transmittance was measured and used to study some optical properties for these crystals. Pure GZS crystal has high optical transmittance in the whole visible range and UV transparency with lower cut off wavelength at 300
nm. By adding Co-ions to GZS crystal, the transmittance decreases and the value of cut off shifts to the higher wavelengths with increasing Co ratio. Adding Co-dopants to GZS crystal has other effects like increasing the magnitude of the absorption coefficient (
α) and forming an absorption band around 2.1
eV. The height of this absorption band increases with increasing Co ratio. The optical energy gap (
E
g
) for pure GZS crystal is about 3.80
eV. This value decreases with increasing Co ratio to GZS crystals. The predominant optical transition for pure and Co-doped GZS crystals is the allowed indirect one. The phonon energy (
E
p
) and the phonon equivalent temperature (
T
p
) at room temperature are 0.20
eV and 2318.84
K for pure GZS crystal, respectively, and these values increase with increasing Co content in GZS crystals.