Quantification of Iron (Fe) in Lithium Niobate by Optical Absorption

Ciampolillo, Maria Vittoria; Zaltron, Annamaria; Bazzan, M.; Argiolas, N.; Sada, Cinzia

doi:10.1366/10-06015

Cited by 24 publications

(20 citation statements)

References 5 publications

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“…This fosters the optical excitation via the iron C-band, though an excitation via the D-band cannot be excluded. We additionally need to consider that the cross-sections of these two excitation paths are very similar at 355 nm [27], i.e, a contribution of both paths to the transient spectrum is to be expected. In this sense, and in direct comparison with the discussion of the previous section, it is likely to assume that the observed NIR absorption feature with fast decay in the spectra of Fig.…”

Section: Excitation Via the Iron D-band + C-bandmentioning

confidence: 99%

Pulse-induced transient blue absorption related with long-lived excitonic states in iron-doped lithium niobate

Messerschmidt

Bourdon

Brinkmann

et al. 2019

Opt. Mater. Express

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Transient absorption is studied in Fe-doped lithium niobate single crystals with the goal to control and probe a blue absorption feature related with excitonic states bound to Fe Li defect centers. The exciton absorption is deduced from the comparison of ns-pump, supercontinuumprobe spectra obtained in crystals with different Fe-concentration and Fe 2+/3+ Li-ratio, at different pulse peak and photon energies as well as by signal separation taking well-known small polaron absorption bands into account. As a result, a broad-band absorption feature is deduced being characterized by an absorption cross-section of up to σ max (2.85 eV) = (4 ± 2) • 10 −22 m 2. The band peaks at about 2.85 eV and can be reconstructed by the sum of two Gaussians centered at 2.2 eV (width ≈ 0.5 eV) and 2.9 eV (width ≈ 0.4 eV), respectively. The appropriate build-up and decay properties strongly depend on the crystals' composition as well as the incident pulse parameters. All findings are comprehensively analyzed and discussed within the model of Fe 2+ Li − O − − V Li excitonic states.

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Section: Excitation Via the Iron D-band + C-bandmentioning

confidence: 99%

Pulse-induced transient blue absorption related with long-lived excitonic states in iron-doped lithium niobate

Messerschmidt

Bourdon

Brinkmann

et al. 2019

Opt. Mater. Express

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“…The sample with the highest doping level was chemically reduced under a mixture of Ar − H 2 atmosphere at 500 K for several hours. The absorption coefficient at 532 nm was measured for samples Fe:LN 0.02 mol % and Fe:LN 0.05 mol %, from which the Fe 2+ concentration was obtained [20]. For sample Fe:LN 0.1 mol %, instead, due to the high absorption level, we preferred to use the datum at 1128 nm [21] from which the Fe 2+ concentration was also deduced.…”

Section: Samplesmentioning

confidence: 99%

Small Polaron Hopping in Fe:LiNbO3 as a Function of Temperature and Composition

et al. 2018

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Small-polaron hopping involved in charge transport in Fe-doped congruent lithium niobate is investigated as a function of temperature and composition by means of light-induced transient absorption spectroscopy. The relaxation dynamics of the light-induced polaron population is characterized by individual activation energies within different temperature ranges. A numerical investigation carried out by Monte Carlo simulations reveals that these findings may be understood in terms of the varying abundance of the different types of hops that the polarons may perform among regular or defective lattice sites. The role of the temperature and of the sample composition on the distribution of the different hop types is thus explored for a wide range of parameters, allowing one to preview the charge transport properties for a given set of experimental conditions.

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“…Quite surprisingly, there exist few experimental and theoretical studies reporting on the direct investigation of the most basic characteristics of the Fe bound polaron, i.e., the local distortion produced by the self-trapping action and its electronic structure. Generally, the incorporation of Fe in LNB was experimentally studied only from the point of view of lattice site location and determination of the Fe valence state [14][15][16][17][18][19][20][21][22][23][24]. However, some recent XRD results [25] showed that the electron capture by the Fe center produces a strain in the crystal matrix, indicating the onset of a measurable deformation at the Fe centers when their valence is changed from Fe 3+ to Fe 2+ by a reduction treatment.…”

Section: Introductionmentioning

confidence: 99%

Polaronic deformation at theFe2+/3+impurity site inFe:LiNbO3crystals

et al. 2015

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Iron doped LiNbO 3 crystals with different iron valence states are investigated. An extended x-ray absorption fine structure (EXAFS) spectroscopy study highlights evident changes in the local structure around iron that can be ascribed to the presence of small polarons. In particular, when a Fe 3+ replaced a Li ion, the oxygen octahedron shrinked with respect to the pure material, with an average iron-oxygen bond value very similar to that of Fe 2 O 3 hematite. When adding an electron, it localizes at the Fe site in a configuration very close to the atomic Fe d orbitals, inducing a relaxation of the oxygen cage. The same system was modelled by spin-polarized density functional theory (DFT). Several local as well as hybrid exchange-correlation functionals were probed on the bulk LiNbO 3 structural properties. The computation is then extended to the case of hematite and finally to the Fe defect in LiNbO 3. The calculations reproduced with good accuracy the large lattice relaxation of the oxygen ligands associated to the electronic capture at the Fe center that can be interpreted as due to the polaron formation. The calculations reproduce satisfactorily the available EXAFS data, and allow for the estimation of the polaron energies and the optical properties of the defect.

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Quantification of Iron (Fe) in Lithium Niobate by Optical Absorption

Cited by 24 publications

References 5 publications

Pulse-induced transient blue absorption related with long-lived excitonic states in iron-doped lithium niobate

Pulse-induced transient blue absorption related with long-lived excitonic states in iron-doped lithium niobate

Small Polaron Hopping in Fe:LiNbO3 as a Function of Temperature and Composition

Polaronic deformation at theFe2+/3+impurity site inFe:LiNbO3crystals

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