Luminescence Properties and Judd–Ofelt Analysis of Various ErF3 Concentration-Doped BaF2 Crystals (original) (raw)
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Growth and characterization of ErF3 doped BaF2 crystals
Journal of Crystal Growth, 2020
ErF 3 doped BaF 2 crystals were obtained using the vertical Bridgman technique. Five crystals, with 0.05, 0.08, 0.1, 0.2 and 0.5 mol% ErF 3 added to the starting material, have been investigated. The optical absorption spectra reveal the characteristic bands of the Er 3+ ions. The distribution of Er 3+ ions along the crystals was studied using the optical absorption spectrum of every samples (14-18 slices) cleaved from the as-grown crystals. The Er 3+ ions are not uniform distributed along the BaF 2 crystals. The segregation coefficient, k, was calculated using the so-called optical absorption method and the Scheil relationship between the dopant concentration and crystal growth conditions. The calculated segregation coefficient of the Er 3+ ions ranges from 0.76 to 0.98, for ions with trigonal (C 3v) sites, and from 0.6 to 0.86 for clusters, depending on the ErF 3 concentration. In the investigated temperature range, only one type of dielectric relaxation has been observed. This relaxation, with activation energy of 0.54 eV is associated with trigonal NNN type (C 3v) centers. The charge compensating defects were discussed taking into account both the optical absorption spectra and the calculated number of NNN dipoles whose relaxation were observed.
Spectroscopic properties of gamma irradiated CeF3 doped BaF2 crystals
TIM 19 PHYSICS CONFERENCE, 2020
The spectroscopic properties of the gamma irradiated BaF 2 :Er 3+ crystals were studied. BaF 2 :0.2 mol% ErF 3 crystal was grown using the vertical Bridgman method. The Judd-Ofelt intensity parameters, Ω t (t = 2,4,6) for f-f transitions of Er 3+ ions were determined from optical absorption spectra recorded before and after gamma irradiation at various doses. The influence of gamma irradiation dose on the Judd-Ofelt parameters and on the radiative transition probability, on the branching ration and on the radiative lifetime was also investigated. The predicted radiative lifetimes were compared with those measured and with those reported by other authors. Apart from the green and red emissions, arising under excitation at 378 nm, a new UV emission band around 321 nm was observed under excitation at 290 nm. This emission was not reported before. Using the Füchtbauer-Ladenburg method, the emission cross section and optical gain parameter of the red and green emission band were calculated.
Optical Materials, 2019
Photoluminescence (PL), thermoluminescence (TL) emission spectra and TL glow curves of barium yttrium fluoride (BaY 2 F 8-BaYF), undoped and doped with erbium (Er 3+) or praseodymium (Pr 3+) were measured to investigate the fundamental absorption (band gapE g), the nature of the trapping centers, as well as the electronic transitions of Ln 3+ in BaYF host. The band gap energy E g of BaY 2 F 8 was determined by vacuum ultraviolet (VUV) excitation measurements to be around 11.2 eV. Additionally, the electronic transition from excited states of Ln 3+ ions and the exciton state were also identified. TL emission spectra showed that the TL emission of doped samples is related to the Ln 3+ ion, indicating that the related host trapping centers are not affected by the new trapping centers originated due the dopant ions. Trap depths were calculated by fitting the glow curves using a first order kinetics model. Host-related trapping centers were attributed to intrinsic defects such as V k and F centers and the new TL peaks observed for Ere and Pr-doped samples was associated to the electrons trapping centers. These results lead us to propose a simple model to explain the origin of the TL emission in BaYF.
Growth and spectral properties of Er3+/Tm3+ co‐doped LiYF4 single crystal
Crystal Research and Technology, 2013
High quality Er3+/Tm3+:LiYF4 single crystals were grown by a Bridgman method. The absorption spectra and luminescent properties of the crystals were studied to characterize the effect of Tm3+ on the spectroscopic properties upon excitation of an 800 nm laser diode. The broaden 1.5 μm and the enhanced 2.7 μm emission were observed in the Er3+/Tm3+ co‐doped LiYF4 single crystals. Meanwhile, the up‐conversion and 1.5 μm emission intensities from Er3+ decrease with increasing the ratio of Tm3+ to Er3+. The energy transfer processes between Tm3+ and Er3+ in the Er3+/Tm3+ co‐doped samples were analyzed. The energy transfer efficiency ηETE from Er3+ to Tm3+ is calculated. The highest ηETE of 65.30% for the sample with 0.296 mol% of Er3+, 0.496 mol% of Tm3+ concentration was obtained. The present work indicates that Er3+/Tm3+ co‐doped LiYF4 single crystal can be a promising material for the potential application in infrared devices.
Comparative spectroscopy of (ErF 3)(PbF 2) alloys and Er 3+-doped oxyfluoride glass-ceramics
Optical Materials, 2004
We have prepared polycrystalline alloys x(ErF 3 ):(100 À x)(PbF 2 ), x = 1, 10. A comparison of their low temperature absorption and emission spectra with the respective spectra of transparent oxyfluoride glass-ceramics, 32(SiO 2 )9(AlO 1.5 )31.5(CdF 2 )18.5(PbF 2 )-5.5(ZnF 2 ):3.5(ErF 3 ) mol%, indicates that the nano-crystalline phase in this glass-ceramic is Er 3+ -doped PbF 2 .
Luminescent properties of solid solutions in the PbF2-EuF3 and PbF2–ErF3 systems
Journal of Luminescence, 2021
Lead fluoroborate glasses doped with Eu 3+ are synthesized, studied, and used to produce glassceramics by heat treatment. The structure of glass-ceramics is determined by X-ray diffraction. The optical, mechanical, and luminescent properties of the glass-ceramics are studied. The structure and spectral-luminescent properties of solid solutions in the PbF 2 -EuF 3 system obtained by both solid-phase reaction and coprecipitation from solutions are investigated.
Materials, 2021
Glass-ceramics with the composition B2O3-Bi2O3-SrF2 were synthesized by the conventional melt-quenching technique and subsequent crystallization of the parental glasses. The temperature at which the ceramization was carried out was selected based on differential scanning calorimetry (DSC) analysis. The structure of the studied materials and the formation of SrF2 nanocrystals were confirmed by the Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. It was found that the amount of strontium fluoride introduced into the parental borate-bismuth glass has a significant impact on the growth of SrF2 nanocrystals. In particular, the influence of the crystalline SrF2 phase on luminescence intensity and kinetics was studied using Eu2O3-doped samples. An increase in luminescence intensity was observed in the samples in which SrF2 nanocrystals were formed. This is most likely related to the fact that some of the Eu3+ io...
Spectroscopic Properties of Pb2+-Doped BaF2 Crystals
Crystals
Various concentrations of PbF2-doped BaF2 crystals were grown by the Bridgman method using a shaped graphite heater. The room temperature optical absorption spectra showed two UV absorption bands (labeled A and D), characteristic of the Pb2+ ions. The structure of the bands was analyzed using the Gaussian multi-peak fitting. The distribution of the Pb2+ ions along the crystals and the effective segregation coefficient were studied using the optical absorption method. The obtained effective segregation coefficient was >1. The Pb2+ ions were not uniformly distributed along the samples. High intensity emission bands were observed in the near UV domain and the visible region.
Nd concentration dependence on the optical and scintillation properties of Nd doped BaF2
Optical Materials, 2010
Nd concentration dependence on the scintillation properties of Nd x Ba 1Àx F 2+x (x = 0.001-0.5) crystals were investigated. From X-ray induced emission spectra, the intensity from an intrinsic luminescence of BaF 2 including core-valence luminescence and self-trapped-exciton (STE) emission were decreased with an increase of Nd concentration. Decay times under 241 Am a-ray excitation were evaluated by the Photomultiplier Tube (PMT) Hamamatsu R8778 that was sensitive across the vacuum ultra-violet (VUV) and visible wavelength range. The average decay times indicated that Nd doped BaF 2 with lower Nd concentration has obviously slower decay times than that of samples with higher Nd concentration because the decay time of STE emission was slower than that of the core-valence luminescence in BaF 2 and the emission of 5d-4f transition on Nd 3+ . The light yield of fast Nd 3+ 5d-4f luminescence was quite lower than STE emission of BaF 2 .
Effects of the HfO2 sinterization temperature on the erbium luminescence
Journal of Luminescence, 2014
The effect of the sinterization temperature of erbium doped hafnium oxide on erbium ion luminescence is studied. Samples were prepared using sinterization temperatures of 400, 600, 800, and 1000 1C over periods of 12 and 24 h. Transitions from the excited states 4 F 7/2 and 4 S 3/2 to the ground state 4 I 15/2 are identified, and this allows for the study of the incorporation of Er 3 þ in the HfO 2 matrix. Results show that the Er 3 þ ions can occupy different sites in the host and the resulting optical behavior depends on the sinterization temperature. The emission efficiency does not depend exclusively on the sinterization temperature but also on the site occupied in the host matrix.