Erbium Luminescence Research Articles

Enhanced luminescence of erbium doped Ga2O3 films and devices by optimizing annealing process

Silicon based erbium doped Ga2O3 films and devices are fabricated. It is found that the intensity of Er3+ ions emission can be enhanced by optimizing the content of sensitizer as well as increasing the optical activity of Er3+ ions in the way of adjusting the annealing process. The indirectly excited luminescence of Er3+ ions can be improved, as measured by photoluminescence and electroluminescence, via selecting N2 as the ambient, decreasing the annealing temperature or prolonging the thermal treatment time. Herein, light emitting devices present the maximum optical power density of ∼0.84 μW/cm2. This work proposes a way to optimize the indirect emission by regulating the content of sensitizers and the optical activity of Er3+ ions, beneficial to the practical use of electrically-driven silicon-based light sources.

Synthesis and cathodoluminescence of YPO4 and LuPO4 single crystals activated with Er3+

Yttrium and lutetium xenotime-structured orthophosphates doped with trivalent erbium have been synthesized in the form of single crystals using flux method in the melt of Li2MoO4-MoO3 in air. Structural parameters, coherent scattering region and average microstrain have been determined by the X-ray diffraction technique. Cathodoluminescent study has shown an inhomogeneous distribution of defects, which initiate luminescence, although electron-probe microanalysis has shown a uniform distribution of Er activator in crystal matrices. The effect of intrinsic defects on the intensity of erbium luminescence bands has been studied and discussed.

Structural, luminescence and nonlinear optical properties of erbium doped barium tellurite glasses for photonic applications

Structural, luminescence and nonlinear optical properties of erbium doped barium tellurite glasses for photonic applications

Up-conversion luminescence and broadband white-light emission in La1-xErxGa0.5Sb1·5O6, Bi1-xErxGeSbO6

In this paper, we first synthesized La1-xErxGa0.5Sb1·5O6 and Bi1-xErxGeSbO6 phosphors with rosiaite structure and studied their spectral luminescent properties. We demonstrated the influence of the matrix composition on the intensity ratio of the Er3+ luminescence bands, due to the transitions from the 2H11/2, 4S3/2, 4F9/2, 4I9/2, and 4 I11/2 excited states to the 4I15/2 ground state upon excitation to the 4I13/2 level. It is shown that the increase in the intensity ratio of the bands corresponding to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions is more pronounced for La1-xErxGa0.5Sb1·5O6 compounds compared to Bi1-xErxGeSbO6. This indicates that the processes of interaction in the studied matrices are different.Along with the luminescence of erbium, broadband thermal white-light emission was detected in highly doped samples after increasing the power density of the exciting radiation with λexc. = 1550 nm. For La1-xErxGa0.5Sb1·5O6 compounds, it occurs at a lower power density than for Bi1-xErxGeSbO6, which may be due to the features of interactions of RE ions with the host, as well as with the particle morphology.

Near-infrared luminescence of erbium doped Ga2O3 films and devices based on silicon: Realization of energy transfer

1.54 μm photoluminescence and electroluminescence are achieved from erbium doped Ga2O3 films on silicon substrates and corresponding devices fabricated by sputtering, respectively. Efficient energy transfer between Ga2O3 and erbium ions is realized in optical pumping, with the energy transfer efficiency of 54.9%. The ∼1.54 μm electroluminescence of erbium ions here is proved to originate from indirect excitation, different from the conventional impact excitation by hot electrons. Herein, the light emitting devices present a turn-on voltage of ∼13 V and onset electric field of 1.4 MV/cm. This work demonstrates the potential of preparing practical electrical-driven silicon-based light sources from erbium doped Ga2O3 films.

Luminescence and structural properties of ytterbium and erbium co-doped LaGaO3 nanophosphor for up-conversion by polyol method

Ytterbium and erbium co-doped lanthanum gallate (LaGaO3) up-conversion phosphors have been synthesized using polyol method followed by heating at 1000°C. From Fourier transform infrared (FTIR) spectroscopy and thermal analysis studies of as prepared sample, formation of hydroxy carbonate precursor has been confirmed. This precursor undergoes two step decomposition leading to the formation of LaGaO3 phase. Detailed X-ray diffraction studies confirmed the formation of orthorhombic LaGaO3 phase with distorted GaO6 octahedra and distorted LaO12 cuboctahedra. As the annealing temperature increased from 1000°C to 1200°C, green to red ratio (GRR) as well as lifetime values increased and this is explained based on the increase in crystallite size from 40 nm to 95 nm and associated decrease in the extent of quenching (non-radiative) processes. Variation in the “n” values accounts for the observed increase in the GRR values corresponding to 1000°C and 1200°C annealed samples with increase in laser power.

Up-conversion luminescence of hafnium, erbium, ytterbium and lithium co-doped yttrium oxide

UP-conversion luminescence of hafnium, erbium, ytterbium and lithium multiple doped yttrium oxide powders are presented. The measured luminescent spectra were obtained using two different lasers with wavelengths of 980 and 1534 nm; emission peaks were observed in the ranges of 530–580 nm (green emission), 630–680 nm (red emission), 960–1100 nm (infrared emission) and 1510 to 1560 (infrared emission) corresponding to the different intra electronic energy levels transitions of the Er3+ and Yb3+ ions. These emission peaks manifest the interactions between these ions that propitiate the phenomenon of up-conversion. The incorporation of lithium in the samples allowed an increase in the luminescent emission of up to 88% for the red emission and up to 12% for the emission in the IR range with respect to the samples that were not doped with lithium. The powders, object of this study, were synthesized by means of the solvent evaporation technique using nitrates and chlorides as precursors. The analysis of XRD showed a cubic crystalline structure of yttrium oxide with the spatial group: Ia-3 (206). The obtained SEM images showed a granular morphology only for samples doped with lithium with dimensions less than a micron. The chemical composition was obtained by measurements of EDS and FT-IR and finally the decay times of the different luminescent emissions are also reported.

Synthesis and luminescence properties of Er3+ doped La3NbO7 ceramic powder

La3NbO7 compounds doped with Er3+ were synthesized by conventional solid state reaction. X-ray diffraction (XRD) and scanning microscopy (SEM-EDS) were used to analyze the morphology and microstructure of this ceramic powder. Rietveld's refinements show that the samples exhibit an orthorhombic weberite structure that can be described using the Cmcm spatial group. A gradual reduction of the unit cell (lattice parameters) with the erbium content evidences the effective substitution in the structure of La3+ ions with the smaller Er3+ ions. The erbium luminescence capabilities were studied using absorption and photoluminescence techniques in the visible (VIS) and near infrared (NIR) regions. The characteristic green, red and NIR Er3+ luminescence bands were obtained under excitation with several wavelengths in the VIS-NIR region, being characterized by a strong multicenter structure. Up-conversion luminescence channels have also been studied to put in value the potentiality of Er3+ doped La3NbO7 as a new phosphor.

Erbium luminescence in (Y, Er, Yb)3Al5O12 powders

In this work, the Stokes and anti-Stokes luminescence (upconversion) of erbium in powders of yttrium-aluminum garnet with various concentrations of erbium, as well as co-doped with erbium and ytterbium, synthesized by the sol-gel method using multistage thermal processing, was investigated. It was established that the phase composition of the resulting powders corresponds to the crystal structure of garnet. For all powders, high-intensity Stokes luminescence with a maximum at 1.53 μm was observed due to the I13/24→I15/24 electronic transition, and anti-Stokes luminescence was observed with the most intense band in the region of 0.65–0.69 μm, associated with the F9/24→I15/24 transition of Er3+ ions. The highest intensity of the Stokes luminescence is observed for the maximum substitution of yttrium by erbium considered here, which corresponds to the Yb1.5Er1.5Al5O12 stoichiometry. The highest intensity of the anti-Stokes luminescence is for the lowest erbium concentration and for codoping with ytterbium with Y2.71Er0.29Al5O12 and Y2Er0.5Yb0.5Al5O12 stoichiometries, respectively.

Preparation of Er-doped Yb3(Al, Fe)5O12 garnets

This work focuses on mixed YbAG/YbIG garnet in a progressive substitution Al/Fe, where aluminium and iron occupy the tetrahedral or octahedral cation sites. In addition to it, the prepared garnet samples were doped with erbium that can profit from ytterbium-based matrix increasing so its absorption cross section. Bulk samples of Er-doped ytterbium – aluminium garnet (Yb2.94Er0.06Al5–xFexO12; x = 0–5) were prepared by a sol-gel method based on Pechini process with citric acid and ethyleneglycol as polyesterification agents. The annealing had to be carried out in oxygen atmosphere in order to stabilize FeIII in the phase equilibrium. Photoluminescence in the range of 1450–1650 nm was measured and the influence of iron doping on erbium luminescence properties was established.

Problems of development of tunable hybrid bismuth – erbium fibrelasers

Experimental data and experience in the development of tunable fibre lasers based on active bismuth centres in silica glasses with different compositions and luminescence bands in the range 1200–1800 nm are considered. It is shown that continuous-wave narrow-band laser radiation with a milliwatt power (1–10 mW) covering this wavelength range can be obtained using hybrid fibre schemes and, probably, co-doping of matrices with bismuth and erbium. Continuously tunable bismuth fibre lasers with partially overlapping spectral ranges of 1270–1370, 1360–1540, and 1600–1800 nm are studied. Hybrid schemes of fibre lasers emitting in the spectral range from 1500 to 1600 nm, which includes the erbium luminescence band, are proposed.

Erbium Luminescence Centres in Single- and Nano-Crystalline Diamond-Effects of Ion Implantation Fluence and Thermal Annealing.

We present a fundamental study of the erbium luminescence centres in single- and nano-crystalline (NCD) diamonds. Both diamond forms were doped with Er using ion implantation with the energy of 190 keV at fluences up to 5 × 1015 ions·cm−2, followed by annealing at controllable temperature in Ar atmosphere or vacuum to enhance the near infrared photoluminescence. The Rutherford Backscattering Spectrometry showed that Er concentration maximum determined for NCD films is slightly shifted to the depth with respect to the Stopping and Range of Ions in Matter simulation. The number of the displaced atoms per depth slightly increased with the fluence, but in fact the maximum reached the fully disordered target even in the lowest ion fluence used. The post-implantation annealing at 800 °C in vacuum had a further beneficial effect on erbium luminescence intensity at around 1.5 μm, especially for the Er-doped NCD films, which contain a higher amount of grain boundaries than single-crystalline diamond.

Quantitative description of yttrium aluminate ceramic composition by means of Er+3 microluminescence spectrum

The composition of erbium-doped yttrium aluminate ceramics was analyzed by means of confocal luminescence spectroscopy, EDX, and X-ray diffraction. A well-defined linear correlation was found between a proposed estimator computed from the luminescence spectrum and the proportion of ceramic phases coexisting in different samples. This result shows the feasibility of using erbium luminescence spectroscopy to perform a quantitative determination of different phases of yttrium aluminates within a micrometric region in nanograined ceramics.

Spectral properties of glass (15Ga2S3 · 85GeS2) doped with erbium

For chalcogenide glasses in the system (1 – x)[0.15Ga2S3 · 0.85GeS2] · xEr2S3, the absorption and luminescence spectra are investigated and the X-ray diffraction analysis is performed. A small shift in the position of the erbium absorption band with the increase of its content in the glass indicates the decrease of the effective charge on it, while the negligible changes in the angle position of the first sharp diffraction peak points to the constancy of the glass’s intermediate-order parameter. The possibility of describing the dependence of the intensity of erbium luminescence on its concentration using the earlier suggested equation has been discussed.

The influence of silver ion exchange on the luminescence properties of Er-Yb silicate glasses

A set of zinc-silicate glasses with different ratios of Er-Yb as well amount of Zn was fabricated. The preparation of silver doped glasses was carried out using the Ag-Na ion-exchange method to enhance Er-Yb luminescence properties of the material. The samples were also annealed for 1–5 h to further support the creation of silver nanoparticles. Intensive absorption at 980 nm was observed in absorption spectra after ion exchange and annealing as well. Also luminescence spectra in the near-infrared range were measured and results showed positive effect of ion exchange process on luminescence properties. Luminescence intensity at 1530 nm was increased almost three times. Possible mechanisms responsible for the increase of the luminescence intensity are also discussed in this paper. We suggest that the enhancement of erbium luminescence intensity is caused by the energy transfer from isolated Ag+ ions to Er.

Properties of erbium luminescence in barium borophosphate glasses

Barium borophosphate glasses doped with five concentrations of Er2O3 were prepared by a melted-quenching process. The properties of glasses have been investigated through density, molar volume, absorption and emission spectra measurements. The obtained density and the calculated molar volume values increased with increasing Er2O3 contents. The absorption spectra of glasses were found to have eleven absorption bands at 362 (4I15/2→4G9/2), 379 (4I15/2→4G11/2), 407 (4I15/2→2G9/2+4H9/2), 450 (4I15/2→4F5/2), 488 (4I15/2→4F7/2), 521 (4I15/2→2H11/2), 544 (4I15/2→4S3/2), 652 (4I15/2→4F9/2), 803 (4I15/2→4I9/2), 978 (4I15/2→4I11/2) and 1537 nm (4I15/2→4I13/2). At 521 nm excitation wavelength, the photoluminescence spectra showed highest peak around 1530 nm (4I13/2→4I15/2). The emission intensity depends on Er3+ ion concentration and shown higher emission intensity with increasing concentration of Er2O3.

Upconversion luminescence of a transparent glass ceramics with hexagonal Na(Gd,Lu)F4 nanocrystals

Novel Er3+ doped transparent glass ceramics containing hexagonal Na(Gd,Lu)F4 nanocrystals were prepared from oxyfluoride glasses. The distribution of rare earth ions in the crystalline and glassy phase has been analyzed by X-ray diffraction and erbium luminescence decay kinetics measurement. A strong deviation of rare earth ion content in fluoride nanocrystals in comparison to the base glass has been observed. Preferential incorporation of Gd3+ over Lu3+ ions in the fluoride lattice leads to the stabilization of hexagonal Na(Gd,Lu)F4 structure and prevents the formation of cubic fluorite type solid solutions. A considerable enhancement of upconversion luminescence correlates with the formation of hexagonal solid solutions and is attributed to an efficient energy transfer between Er3+ ions.

Structure features of the sodium-germanate glasses doped with ytterbium erbium retrieved from raman spectroscopy

Subject of Research.The paper deals with study of Raman spectra and luminescence spectra in the visible region of the sodium-germanate glass: 49 GeO2 – 13 Na2O – 27 Yb2O3 – 11 La2O3 - 0,25 Er2O3 and presents research results. In addition, this glass is doped with 5 mol% of the following components MgO, BaO, Al2O3, PbO, Nb2O5, TiO2, SiO2, P2O5 in order to study the effect of these additives on the structure of the glassy matrix and the anti-Stokes luminescence spectra of erbium ions. Method. Raman scatteringspectra were recorded by Renishaw inVia Raman Microscope. Excitation source is a helium neon laser (λ= 633 nm) with power equal to 50Wt. Anti-Stokes luminescence of erbium ions was registered in spectral region of 450–750 nm at room temperature (excitation laser wavelength is 975 nm, power is 1Wt). Main Results. It was shown that the structure of the initial glass does not change with the introduction of niobium as Nb2O5 in any coordination plays a role of network forming, building a single mixed grid with tetrahedrons [GeO4]. Introduction of the second glass former P2O5 leads to loosening germanate structure due to the appearance of the phosphate sublattice. This leads to a redistribution of the relative intensity of up-conversion luminescence bands with maxima at 540 and 670 nm compared with the initial glass. Introduction of additives PbO, MgO, Al2O3, TiO2 results in a multicenter structure. In case of titanium oxide addition it leads to a change in the relative intensities of the erbium luminescence.

Oxygen and erbium distribution in diffusion doped silicon

Silicon doped with rare-earth metal erbium is a promising material for the fabrication of highly efficient light emitting structures that can be easily integrated into silicon electronics. The fabrication technology of these structures includes little if any diffusion processes because the efficiency of erbium luminescence in diffusion structures is low. It is still unclear what causes this low erbium luminescence efficiency: low impurity concentration, low optical activity of the luminescence centers or luminescence extinction by the defects. The composition of diffusion silicon layers doped by rare earth erbium has been investigated. The diffusion source was an erbium oxide layer on the surface of the test silicon wafer. The erbium and oxygen distribution profiles in silicon have been measured by SIMS. The concentration of electrically active erbium impurity in the diffusion layers on silicon has been determined by measuring the surface resistance and carrier mobility during consecutive etching of layers. The erbium diffusion coefficient at 1240°C has been estimated to be 4.8·10–13cm2·s−1. The concentrations of electrically active (8·1016cm−3) and total (3·1018cm−3) erbium in the surface silicon diffusion layers prove to differ noticeably in the presence of high oxygen concentration (>1019cm−3). A model of erbium and oxygen simultaneous diffusion has been suggested. The model takes into account the association of erbium and oxygen into complexes. The results of numerical simulation and experimental data are in a good agreement for the near-surface region of the diffusion layer.

The influence of silver-ion doping using ion implantation on the luminescence properties of Er–Yb silicate glasses

A set of zinc-silicate glasses with different ratios of erbium and ytterbium was fabricated. To achieve Ag-rich thin films in a sub-surface layer, ion-implantation technique at an energy of 1.2MeV and 1.7MeV with a fluence of 1×1016cm−2 was used. Post-implantation annealing was also applied. Changes in the spectroscopic and lasing properties of erbium ions as a function of implantation fluence of silver were studied with the aim to assess the positive effect of silver as a sensitiser of erbium luminescence. Therefore, absorption spectra in the visible range as well as luminescence spectra in the near-infrared range were measured and partially also the 4I11/2–4I15/2 transition of the erbium ion was studied. The results showed that silver positively influenced luminescence intensity at 1530nm by increasing it almost three times. The biggest increase was achieved in glass with the highest concentration of erbium. Luminescence lifetime was not significantly influenced by the presence of silver and still remained around 10ms.