Spectroscopic Analysis on Sm3+ Doped Fluoroborate Glasses
Optical behaviors of the Sm3+ doped (50 − x) B2O3 + 25ZnO + 25NaF + xSm2O3, (where x = 0.05, 0.1, 1, 2 and 3 wt%) glasses have been studied and reported. The glasses were prepared by following melt-quenching technique and the optical absorption spectra in
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Abstract Optical behaviors of the Sm3+ doped (50 − x) B2O3 + 25ZnO + 25NaF + xSm2O3, (where x = 0.05, 0.1, 1, 2 and 3 wt%) glasses have been studied and reported. The glasses were prepared by following melt-quenching technique and the optical absorption spectra in the UV-vis-NIR region between 350 and 1800 nm and the luminescence spectra between 550 and 750 nm, have been measured for the prepared glasses at room temperature. Optical band gap, band tail parameter, and Urbach energy have been calculated from the fundamental absorption edges for direct and indirect transitions. The band gap value is found to decrease with the increasing concentration of the Sm3+ ions. The band gap values are found to be 3.075–2.011 eV for direct transitions and 3.408–2.661 eV for indirect transitions. The origin of the Urbach energy has been identified and discussed. The Urbach energy is found to increase considerably with the increase in Sm3+ ions and is found to have values from 0.2268 to 0.8854 eV. A strong luminescence in the reddish-orange spectral region has been observed for the prepared Sm3+ glasses. Keywords Glasses • Bonding parameters • Luminescence • Urbach’s energy
1 Introduction Rare-earth (RE) doped B2O3 glasses are used for the development of electronic and optoelectronic devices, lasers, sensor devices, optical fibers, amplifiers, and hole burning high-density memories because of their excellent properties like super hardness, high insulation, linear, and nonlinear optical behavior [1]. There has been a considerable attention in the study on optical, structural, and dielectric behavior of borate-based glasses [2–4]. The excitations and emissions are due to the transition among 4f electronic states of trivalent RE ions, which are highly sensitive to the symmetry, structure of the local environment, and phonon energy of the host matrix [5].
S. Arunkumar · K. Marimuthu (*) Department of Physics, Gandhigram Rural University, Gandhigram 624 302, India e-mail: [email protected]
S. Sathiyamoorthy et al. (eds.), Emerging Trends in Science, Engineering and Technology, Lecture Notes in Mechanical Engineering, DOI: 10.1007/978-81-322-1007-8_57, © Springer India 2012
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The Sm3+ ion exhibits a strong luminescence in the reddish-orange spectral region. Through the optical analysis, the effect of host matrix on the local environment of the given RE cation with its first nearest neighbor could be elucidated using Judd-Ofelt theory [6, 7]. Jayasankar et al. [8] reported the optical properties of Sm3+ ions in lithium borate and lithium fluoroboarte glasses, and Sanmuga Sundari et al. [9] studied and reported the structural and optical behavior of Sm3+ doped sodium borate and fluoroborate glasses. Ali [10] studied the optical band gap of the Sm3+ doped bismuth borate glasses for various inter band transitions using Davis and Mott theory [11, 12]. The present work reports, spectroscopic and band gap studies on Sm3+ doped alkali fluoroborate glasses. Through the ultraviolet absor
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