Yb Concentration Research Articles

Preparation of YbAlN piezoelectric thin film by sputtering and influence of Yb concentration on properties and crystal structure

Aluminum nitride (AlN) is a key material for piezoelectric micro-electromechanical systems (MEMS). Since the discovery of the increase in AlN piezo performance by scandium (Sc) doping, many groups have investigated other effective dopants. However, another effective single dopant has not yet been experimentally demonstrated, although potential effectiveness has been indicated by theoretical calculations. In this study, we propose ytterbium (Yb) as an effective dopant. The sputtering conditions for YbxAl1 − xN films were optimized by design of experiments (DoE). Consequently, high-quality YbxAl1 − xN films were obtained. YbxAl1 − xN with x values ranging from 0 to 0.37 demonstrate good piezo response. A maximum d33 of ~12 pC/N, which is approximately twice the value of non-doped AlN, is achieved. According to crystallographic analysis using X-ray diffraction, the influence of Yb concentration on the crystal structure was similar to that of Sc with differences observed at high Yb concentration.

Laser induced broadband Vis and NIR emission from Yb:YAG nanopowders

The laser induced broadband emission (LIBE) of (YbxY1−x)3Al5O12 nanocrystals was investigated in vacuum using the focused infrared laser beam. The samples were prepared via Pechini's technique. The different shapes of LIBE spectra were observed. The LIBE characteristics including an order of the process, rise and decay times, were independent on the type of emission spectra and concentration of Yb3+ ions. Intensity of the emission spectra decreased/increased with time after switching off/on the laser excitation, while the shape of the emission spectra remained approximately the same. This is consistent with the colour of the emission, which remains white even after significant decrease in intensity. For the first time, the generation of broadband emission begins after reaching a certain “time threshold” in range 0–10 s, and disappearing afterwards. Beforehand, several possible LIBE mechanisms have been proposed for different materials, however they don’t cover all aspects of this phenomenon. In the present article, the intervalence charge transfer (IVCT) model is considered as general for RE doped phosphors. The features of LIBE have been described within this model.

Geodynamic setting of high-Cr chromite mineralization in nascent subduction zones: Li isotopic and REE constraints from the Zambales ophiolite, Philippines

The Acoje block of the Zambales ophiolite in the Northwest Philippines is a remnant of forearc lithosphere that formed during an Eocene subduction initiation event in the Western Pacific Ocean. It hosts abundant high-Cr chromitites in the uppermost part of the mantle sequence and the overlying dunitic Moho transition zone. The host harzburgites of the uppermost mantle sequence vary upward from Cpx-rich to Cpx-poor varieties. Clinopyroxene grains in both types of harzburgites and the dunites have prevalent finger-like protrusions and diopsidic compositions, indicative of melt impregnation. From the Cpx-rich harzburgites to Cpx-poor harzburgites and dunites, the clinopyroxene grains display increasingly depleted major element and rare earth element (REE) compositions, e.g., Al2O3 contents from 5.15 wt% to 0.84 wt% and Yb concentrations from ~ 0.2 ppm to 1.5 ppm. These changes are compatible with a transition from MORB to boninitic affinity, Olivine grains in the dunites and sparsely disseminated chromitites vary widely in δ7Li values, primarily from ~ +1 to +10. Such a δ7Li range implies that the parental magmas of the high-Cr chromitites were derived from mantle sources that were modified by slab fluids and had Li isotopic signatures either similar to, or heavier than, the normal mantle range (+4 ± 2). Partial melting in the mantle sources was triggered by heating of previously hydrated Cpx-rich harzburgites during slab rollback and subsequent asthenospheric upwelling. The upwelling brought asthenospheric materials and high heat flux into the lithospheric mantle, facilitating formation of high-Ca boninitic magmas and high-Cr chromitites in the nascent mantle wedge. The different Li isotopic domains in the mantle sources of the high-Cr chromitites indicate that the mantle temperatures were elevated rapidly after the hydration event in order to generate the boninitic magmas.

Significant Enhancement of Piezoelectric Response in AlN by Yb Addition.

This study employs first-principles calculations to investigate how introducing Yb into aluminum nitride (AlN) leads to a large enhancement in the material’s piezoelectric response (d33). The maximum d33 is calculated to be over 100 pC/N, which is 20 times higher than that of AlN. One reason for such a significant improvement in d33 is the elastic-softening effect, which is indicated by a decrease in the elastic constant, C33. The strain sensitivity (du/dε) of the internal parameter, u, is also an important factor for improving the piezoelectric stress constant, e33. On the basis of mixing enthalpy calculations, YbxAl1−xN is predicted to be more stable as a wurtzite phase than as a rock salt phase at composition up to x ≈ 0.7. These results suggest that Yb can be doped into AlN at high concentrations. It was also observed that the dielectric constant, , generally increases with increasing Yb concentrations. However, the electromechanical coupling coefficient, , only increases up to x = 0.778, which is likely because of the relatively lower values of within this range.

Detailed investigation of absorption, emission and gain in Yb:YLF in the 78–300 K range

We present spectroscopic measurements focusing on a detailed investigation of temperature dependence of absorption, emission and gain in the uniaxial Yb:YLF laser gain medium. Measurements are carried out in the 78–300 K range, but we especially targeted our attention to the 78–150 K interval, which is the desired working range of liquid nitrogen cooled cryogenic Yb:YLF lasers/amplifiers. A tunable (770–1110 nm) Cr:LiSAF laser with around 100 mW continuous-wave output power and sub-0.2 nm bandwidth is used as an excitation source. The average power of the Cr:LiSAF laser is low enough to prevent heating of the sample, and its spectral flux (W/nm) is high enough to enable large signal-to-noise ratio measurements. Measured absorption data is used to cross-check the validity of the emission measurements, while the measured temperature dependent small-signal gain profile provided a second independent confirmation. The acquired absorption cross section curves match the previous literature quite well, whereas the measured strength of c-axis emission is stronger than some of the earlier reports. Direct measurements of small signal gain confirmed the emission cross section data, where single pass gain values above 50 have been measured for the 995 nm transition of E//c axis at 78 K. We further provide simple analytic formulas for the measured temperature dependence of absorption and emission cross section. We hope the presented results to be useful for the development of next generation of cryogenic Yb:YLF laser and amplifier systems.

Structure evolution of Yb substituted PCMO manganites

In the present investigation, we have made an effort to synthesize and study the structure of Yb substituted Pr0.67-xYbxCa0.33MnO3 (PYCMO) [x = 0.0, 0.09, 0.2, 0.4 and 0.6] manganites. The tolerance factor estimated decreases while the A-site variance increases with an increase in Yb concentration. This gives an insight of the impact of Yb on the structure of the system. Detailed Rietveld analysis of the X-ray diffraction pattern suggests the structural changes to be temperature sensitive and a mixed-phase is found to evolve as the concentration of Yb increases. The parasitic secondary phase has been identified as YbMnO3 (YMO) which crystallizes in hexagonal structure. A strong immiscibility of the orthorhombic and hexagonal phases has been evident from the two-phase Rietveld analysis.

Evaluating the connectivity of shale gas wells by new rare element tracers

Three types of rare earth elements, Pr, Yb and Sm, in shale gas well and fracturing fluid, which showed a low content and are environmentally friendly and chemically stable, formed complexes with ethylenediamine tetra-acetic acid and di-picolinic acid, both of which were applied as tracers in the determination of the connectivity of shale gas wells. A case study was made in two shale gas wells (Jiaoye 66-Z1HF and Jiaoye 66-Z2HF) of the middle gas reservoir in the Jiaoye No. 66 extended platform well group in the Fuling shale gas field of SINOPEC. We first injected rare element tracer into the wells, and then evaluated the connectivity of the Jiaoye No. 66 extended platform after fracuring by monitoring whether there was rare element tracer in the tracer-injected wells and the flow-back fluid from adjacent wells, and finally discussed the feasibility of three-dimensional development of the lower, middle and upper gas layers of the Fuling shale gas field. The results of flow-back fluid monitoring showed that a high content of Sm tracer, which had been injected into well Jiaoye 66-Z2HF, was occasionally found in well Jiaoye 66-Z1HF, indicating that there might be a connection between the middle gas layers of the two wells. There is no abnormal Pr, Yb or Sm concentrations in the monitoring wells of the lower gas layers, indicating that they were not connected with the central gas layers. A high concentration of Sm tracer was detected in the mixed back-flow fluid samples of wells Jiaoye 5-S2 and Jiaoye 5-S3 in the upper gas layer, indicating that they were connected to the central gas layers. The present investigation has verified that rare element tracer technology is a facile and effective method for the connection determination between shale gas wells and has broad application prospects.

Experimental and theoretical analysis on pump spectral propriety of single frequency Erbium-Ytterbium co-doped fiber amplifier

The pump spectral propriety of three types of commercial 915 and 976 nm LDs on single frequency Erbium-Ytterbium co-doped fiber amplifier (EYDFA) is theoretical and experimental analyzed. The slope efficiency, ASE intensity and linewidth broadening of the wavelength stabilized or un-stabilized LDs pumped amplifier are compared in detail. The results demonstrate that 976 nm LD pumping exhibits superior to 915 nm LD in efficiency and SNR. Comparing with wavelength stabilized 976 nm LD, the wavelength un-stabilized 976 nm LD with center wavelength deviating from Yb absorption peak and over 4 nm linewidth has better performance in Yb-ASE suppression but slightly lower in efficiency and linewidth broadening. The difference between the two 976 nm LDs could be taped off by increasing the seed power or output power. This work indicate that wavelength un-stabilized 976 nm LD is more suitable for pumping high power single-frequency EYDFA to avoid the bottlenecking effect, and provide reference for the optimal pump selection.

Optical detection and recovery of Yb(III) from waste sample using novel sensor ensemble nanomaterials

In the present study, the novel organic ligand of N,N–bis(salicylidene)1,2–bis(2–aminophenylthio)ethane based optical sensor material was fabricated by direct immobilization approach. The resultant sensor material was maintained with a high surface area with ordered mesoporosity even after successful organic ligand immobilization. The application of ytterbium (Yb(III)) detection, adsorption and recovery was evaluated at an optimum experimental protocol with exhibition of significant color formation. The morphology, porosity, and structure of sensor material were surveyed and the possible mechanism for detection and adsorption of Yb(III) ion on the surface of the sensor material was assumed. The effect of solution pH was carefully evaluated for the determination of optimum experimental conditions. The experimental data clarified that the Yb(III) ion was detected and adsorbed by the sensor material at pH 3.50. The sensor material was able to detect the low concentration of Yb(III) ion as the detection limit was 0.20 µg/L. The data were revealed that the proposed sensor material was not affected with the existing competing ions and the signal intensity and specific color was observed only toward the Yb(III) ion at the experimental condition. The adsorption performance was well fitted with the Langmuir adsorption isothermal model and the maximum adsorption capacity was 169.31 mg/g. The recovery of Yb(III) ion from the sensor material was carried out by 0.30 M HNO3. The outcome of this study suggested a non-toxic, economical, stable, efficient, easy-to-use and novel optical sensor material for the detection, adsorption and recovery of Yb(III) ion from aqueous solutions.

Luminescence-based determination of ytterbium (III) and morin in solution using sorption by transcarpathian clinoptilolite

Sorption-luminescent methods for ytterbium and morin determination based on the clinoptilolite were proposed. Optimal luminescent material preparation condition is the sorption of Yb(III) on the precalcined at 50 °C clinoptilolite in the solution with pH 8.0. The obtained clinoptilolite-Yb(III) sample was treated with morin solution. Definable range of Yb(III) concentration with the detection limit of 0.1 μg·mL−1 is within 0.25–1.0 μg·mL−1. The proposed method can be used for ytterbium determination in the presence of many rare earths. The range of the determination concentrations of morin is 3·× 10−4 − 4·× 10−3 mol·L −1. The detection limit is 1.5·×·10−4 mol·L −1.

Sm3+/Yb3+ co-doped GeO2-PbO glass for efficiency enhancement of silicon solar cells

Abstract Luminescent properties and energy transfer processes in GeO2-PbO glasses co-doped with Sm3+/Yb3+ were investigated. The concentration of Sm3+ was 1 mol% while the concentration of Yb3+ was 0.2 and 0.5 mol%. Judd–Ofelt intensity parameters Ω λ ( λ = 2,4,6 ) were calculated from absorption spectra of the co-doped glass samples, together with transitions probabilities A j j ′ and radiative lifetimes τ R . Visible and NIR emission spectra were obtained under excitation of wavelengths corresponding to the 6H5/2 →(6P7/2,6P3/2,4I11/2) transitions of Sm3+ resulting in different emission channels from 4G5/2 level energy to lower energy levels. The set of co-doped and undoped glasses were placed on the top of a conventional silicon solar cell and the relative efficiency was studied. Cooperative energy transfer between the Sm3+ ion and Yb3+ ion would probably be responsible for observed enhancement in the energy efficiency of about 10%.

Investigation of optical and spectroscopic properties of Nd co-doped Yb:YVO4 single crystals grown by OFZ method

Nd (0.8 at.%) co-doped Yb (0.8 and 3.0 at.%):YVO4 single crystals were grown by optical floating zone technique for the first time to the best of our knowledge. The absorption spectra revealed strong absorption for π-polarization (E||c) than the σ-polarization (E⊥c) for both the Yb concentrations due to anisotropy of the crystal. The estimated effective Judd-Ofelt parameters are 11.8675 × 10−20, 5.1577 × 10−20 and 7.3755 × 10−20 cm−2. Spectroscopic quality factor of Nd co-doped Yb:YVO4 are 0.70. which is lower than that of Nd (1.0 at.%) doped YVO4 (0.97), which indicates the energy transfer from Nd3+ ion to Yb3+ ion inside the host matrix. The estimated emission cross-section of 4F3/2 → 4I11/2 Nd transition with an excitation at 808 nm for both the concentrations of Yb is ∼4.0 × 10−19 cm2 which is almost same as estimated by Bhaumik et al. (2014) [21] for Nd:YVO4. Hence emission cross-section of 4F3/2 → 4I11/2 Nd transition is not effected by Yb co-doping. Also the PL intensity of Yb at 1010 nm enhances with Yb co-doping for same Nd (0.8 at.%) this is because the Nd3+ ion effectively excites the Yb3+ ion in upper state. Therefore Nd3+ ion acts as excellent sensitizer for Yb:YVO4 laser gain medium and make efficient pumping in the gain medium.

Cooperative luminescence of Yb3+ ion pairs in Li6Y(BO3)3:Yb single crystals

Cooperative luminescence (CL) of Yb3+ pairs was investigated in Yb-doped Li6Y(BO3)3 crystals. It was reliably distinguished from other types of up-conversion luminescence related to the energy transfer from Yb3+ ions to other rare-earth ions unintentionally introduced into the crystal. The CL was observed in the region of 19,000–21,000 cm−1 (526-476 nm) under excitation at about 10,285 cm−1 (972.3 nm) by continuous wave or pulsed lasers. The emission band is nearly featureless at room temperature but develops a pronounced line spectrum at low temperatures. The width of the absorption line corresponding to the 2F7/2 → 2F5/2 transition of the Yb3+ ions at 10,285 cm−1 demonstrates an extreme dependence on temperature, increasing by a factor of 250 from 6 to 300 K. The dependence of the CL intensity on laser irradiation power in the continuous wave mode is interpreted by an analytical model based on the intensity saturation effect strongly related to the peak amplitude of the absorption line. The model updates earlier descriptions of this dependence given in terms of power functions with “anomalous” exponents differing from the value of 2 expected for the luminescence of pair centres and accounts for the observed sharp temperature dependence of the saturation intensity. The decay kinetics of CL was shown to be approximately twice as fast as that of a single-ion luminescence, as expected. However, the decay times were found to be decreasing with increasing Yb concentration, which is explained by excitation escape from Yb3+ pairs due to energy transfer along Yb chains.

Synthesis of Yb3+/Ho3+ co-doped Y2O3 nanoparticles and its application to dye sensitized solar cells

In this study, a series of Yb3+/Ho3+ co-doped Y2O3 up-conversion (UC) nanophosphors was fabricated by a homogeneous precipitation method. The photoluminescence emission in the visible regions of the nanophosphors has been investigated under 980 nm IR laser excitation. The nanophosphors exhibited strong visible green and weaker red up-conversion emissions. The effects of various concentrations of Yb3+ (1–4 mol%) on the photoluminescence properties of fabricated nanophosphors was also investigated. The fabricated UC nanophosphors were incorporated in the DSSC and their influence on the photovoltaic performance of the DSSC was characterized by a current-voltage curve, and incident photon to current conversion efficiency. Compared with the DSSC without the UC nanoparticles which had a cell efficiency of 4.27%, the DSSC incorporating Y2O3:Ho3+/ Yb3+ UC nanoparticles showed an enhanced cell efficiency of 4.79%.

Late Mesozoic adakite granites of the southern frame of the eastern flank of the Mongol-Okhotsk orogenic belt: material composition and geodynamic conditions of formation

Granitoids of the Magdagachi complex were studied using new and published petrochemical, geochemical and isotopic (Sm-Nd, Rb-Sr) data. Granitoid samples were taken from the southern frame of the eastern flank of the Mongol-Okhotsk orogenic belt (MOOB). Their analysis shows increased concentrations of Sr, Ba, Eu; reduced concentrations of Nb, Ta; abnormally low concentrations of HREE, Y and Yb; significant fractionation of REE; and high Sr/Y ratios. Therefore, the Magdagachi granitoids are classical adakites that may have formed at a depth of more than 45 km due to melting of eclogite with a garnet content of 20–50 %. Such conditions could exist under subduction as a result of melting of the frontal or lateral parts of the slab in subduction windows formed during oblique subduction at an orthogonal sinking angle. Highly metamorphosed lower crust Precambrian formations were also melted, and a source of parental melts could have been composed of both the mantle and crustal materials. Two tectonic scenarios are proposed that could have been accompanied by the formation of Magdagachi granitoids. Both scenarios refer to subduction processes, but differ in interactions between various regional structures in the Late Mesozoic.

High absorption large-mode area step-index fiber for tandem-pumped high-brightness high-power lasers

A short absorption length ytterbium (Yb)-doped large-mode area (LMA) fiber is presented as a step forward to mitigate the stern problem of nonlinear scatterings in a tandem pumping scheme adopted for high-power fiber laser. The short absorption length was realized by incorporating high Yb concentration in the fiber core. Furthermore, by replacing the inherent silica cladding with a Ge-doped cladding, we were able to obtain low core numerical aperture (NA) and negate the detrimental effect of index-raising by high Yb concentrations. This overcomes the long-standing limitation in step-index Yb-doped fibers (YDFs) where high cladding absorption inevitably results in high NA, thus hampering single-mode operation. We report an LMA ( ∼ 575 μm 2 ) YDF with NA of 0.04 and absorption of 27 dB/m at 976 nm—both traits promote power scaling of single-mode tandem pumped fiber lasers. To our knowledge, this is the highest cladding absorption attained in a low-NA step-index fiber to date. An all-fiber tandem-pumped amplifier was built using only ∼ 14 m of the YDF. The amplifier delivered a near-Gaussian beam ( M 2 ∼ 1.27 ) at 836 W output power (pump power limited) with a high slope efficiency of ∼ 83 % . Thanks to the short length and the tandem pumping, no indication of limiting factors such as stimulated Raman scattering, photodarkening, and transverse mode instability was observed.

The effect of rare earth element (Er, Yb) doping and heat treatment on suspension stability of Y2O3 nanoparticles elaborated by sol-gel method

Sol–gel processing was used to fabricate undoped and rare-earth (Er, Yb) doped very fine Y2O3 nanoparticles under supercritical drying conditions of ethanol using an autoclave and annealed at 500 °C and 800 °C for 2 h. The Er and/or Yb concentration is fixed at 5 mol % for doped and co-doped nanoparticles. The as-synthesized Y2O3 nanopowder was characterized by the X-ray diffraction, scanning electron microscopy and thermogravimetric analysis (TGA) coupled with differential thermal calorimetry (DTA). The effects of solvent, heat treatment and the doping on the suspension stability of yttrium oxide (Y2O3) nanoparticles doped rare-earth elements (Er and Yb) were evaluated by UV-Visible spectroscopy, zeta potential measurement and particle size in suspension, thus, Hamaker 2 software. During this work, the particle analysis showed that the resulting nanoparticles had a pure cubic structure and nano-sized crystallites of about 8–38 nm. The heat treatment of the nanopowders causes a rapid decantation of the suspensions and the Er doped nanoparticles suspension had a good stability.

Anatase–Rutile Transition and Photo-Induced Conductivity of Highly Yb-Doped TiO2 Films Deposited by Acid Sol–Gel Dip-Coating Method

A method to prepare Yb-doped TiO2 is proposed, using titanium isopropoxide and ytterbium oxide. Thin films and powders are produced through the sol–gel technique where the Yb concentrations are 0.01 at.%, 0.02 at.%, 1 at.%, 2 at.% 4 at.% and 8 at.%. The increase in the doping concentration intensifies gradually the sample transparency for the whole observed spectrum and reaches the transparency degree of the undoped sample with the highest concentration of ytterbium. By means of x-ray diffraction (XRD) we find that the solution’s pH leads to the formation of a rutile structure which is compensated for by lanthanide doping, inhibiting the anatase–rutile phase transformation. Then, the XRD profile depends on the Yb concentration, being mostly anatase for undoped and highly (8 at.%) doped samples, with mixed ratios of these two phases in other concentrations. Maintaining an acid solution leads to fewer intergrain defects in the rutile structure contributing to higher conductivity. Photo-induced investigation of 8 at.% Yb-doped thin film, using several light sources leads to distinct behavior concerning the excitation of intra-bandgap states and/or electron–hole pairs. This result helps to understand the electronic transport in Yb-doped TiO2 and shows that devices based on its conductivity may have improved performance by irradiation with controlled light energy.

Ytterbium-implanted photonic resonators based on thin film lithium niobate

We introduce our design, simulation, and fabrication for cm-long waveguides and micro-ring resonators based on fully-etched thin-film lithium niobate on insulator (LNOI) incorporated with rare earth ions. We implant ytterbium ions (Yb3+) into the crystalline host and study their optical properties at 4 K temperature. We measure an intrinsic optical quality factor of higher than 2×106 after postimplantation annealing. We characterize the photoluminescence spectrum, lifetime, and absorption of Yb3+ ions. Incorporation of rare earth ions into LNOI as a crystalline and nonlinear photonic element may enable the development of multi-functional quantum photonic devices capable of generating, transducing, manipulating, and storing of quantum optical information.

Enhanced up-conversion luminescence efficiency of heterogeneous hetero-phase α-NaLuF4:Yb/Er@ β-NaYF4:Yb core-shell structure nanocrystals

The heterogeneous hetero-phase α-NaLuF4:Yb/Er@β-NaYF4:Yb core-shell structure nanocrystals with small particle size can be induced via heterogeneous core induction successfully. And the crystal phase of core-shell structure nanocrystals can be greatly affected through adjusting the amount ratio of core to shell. The mutual induction of phase transformation between heterogeneous core and shell is investigated. Under the 980 nm laser excitation, the luminescence enhancement ability of heterogeneous hetero-phase α-NaLuF4:Yb/Er@β-NaYF4:Yb core-shell structure nanocrystals is much higher than that of the heterogeneous homo-phase core-shell structure nanocrystals synthesized at the same condition. The up-conversion luminescence efficiency of heterogeneous hetero-phase α-NaLuF4:Yb/Er@ β-NaYF4:Yb core-shell structure nanocrystals is highest when the Yb3+ ion concentration in core and shell is the same. In addition, the population of up-conversion red emission can be influenced by enhancing the cross relaxation process when the concentration of Yb3+ ions in shell layer is increased. These results deepen the understanding of the growth and energy transfer process of the core-shell structure nanocrystals and make the heterogeneous hetero-phase α-NaLuF4:Yb/Er@β-NaYF4:Yb nanocrystals suitable for using in the biomedicine application.