Excitations électroniques dans TiO2 rutile et TiO mesure des pertes d'énergie des électrons entre 3 et 60 eV

Frandon, J.; Brousseau, B.; Pradal, F.

doi:10.1051/jphys:01978003908083900

Cited by 22 publications

(9 citation statements)

References 39 publications

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“…In the case of TiO 2 the corresponding interband transitions (i.e. O2p 3 Ti3d) are observed around 6 eV in good agreement with data in the literature [13,14]. Other features observed at 24 eV for TiN and at 25.7 eV for TiO 2 are assigned to transitions between the respective valence band and Ti4sp states [15].…”

Section: Resultssupporting

confidence: 89%

Dielectric Properties of Ti, TiO2 and TiN from 1.5 to 60 eV Determined by Reflection Electron Energy Loss Spectroscopy (REELS) and Ellipsometry

Fuentes

Mancheño

Balbás

et al. 1999

phys. stat. sol. (a)

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The dielectric properties of metallic Ti and thin films of TiO2 and TiN in the energy range from 1.5 to 60 eV have been determined by quantitative analysis of the respective electron energy loss spectra in the reflection mode (REELS). The energy loss function (ELF) of every material, that is proportional to Im {1/ε}, is obtained by trial and error until a good quantitative agreement between the simulated and experimental inelastic electron scattering cross‐sections at three different primary electron energies (i.e. 0.5, 1 and 1.5 keV) is achieved. Kramers‐Kronig transformation is then used to obtain real and imaginary parts of the dielectric function ε(ω). In addition, spectroscopic ellipsometry was used to improve the ELF in the 1.5 to 4.5 eV energy range where it is strongly affected by the experimental energy resolution and the presence of the elastic peak. The characteristic differences among the spectra of the particular compounds are discussed in terms of different electronic properties.

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Section: Resultssupporting

confidence: 89%

Dielectric Properties of Ti, TiO2 and TiN from 1.5 to 60 eV Determined by Reflection Electron Energy Loss Spectroscopy (REELS) and Ellipsometry

Fuentes

Mancheño

Balbás

et al. 1999

phys. stat. sol. (a)

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“…The experimental device and the computation of optical functions were described in detail elsewhere [14]. The primary energy of incident electrons passing through thin films is 20 keV.…”

Section: Samples Preparation and Experimental Proceduresmentioning

confidence: 99%

“…For comparison, the spectra of the corresponding oxides (Sc,O,, Y,O,, ZrO,, HfO,) are also given here. The discussion of the experimental results related to these oxides is difficult, due to the lack of knowledge about their electronic structure and will be drawn from previous considerations about titanium and its two oxide phases T i 0 and TiO, [14].…”

Section: Introductionmentioning

confidence: 99%

Electronic Excitations in Some Transition Metals and Their Oxides. Characteristic Energy Loss Measurements up to 50 eV

Frandon

Brousseau

Pradal

1980

Physica Status Solidi (b)

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The characteristic energy losses suffered b y a 20 keV electron beam through thin films of some transition metals (Sc, Y, Zr, Hf) and of their oxides are measured using a magnetic spectrograph u p t o 50 eV. The energy loss function -1m 1/& and the complex diclectric constant are calculated. It is shown that the electron excitation spectra of metals contain two main contributions in this energy range: one due t o collective excitations of the conduction electrons, the other t o the excitation of inner p-electrons. In the case of oxides the spectra display three strong structures: there are probably two collective excitations of valence electrons followed by the excitation of inner p-electrons of the metal.Les pertes caractkristiques d'6nergie subies par u n faisceau d'6lectrons de 20 keV B la traverske de films minces de quelques m6taux de transitions placks en dkbut de s6rie (Sc, Y, Zr, Hf) e t de leurs oxydes ont 6t6 mesur6es avec un spectrographe magnetique jusqu'i 50 eV. La fonction -1m lie e t la eonstante dielectrique complexe sont calcul6es. On montre que le spectre des excitations 6lectroniques des mbtaux contient deux contributions principales dans le domaine d'6nergie considkrk : l'une due i l'excitation collective du gaz d'klectrons de conduction, l'autre B l'excitation des 6lectrons p. Dans le cas des oxydes, les spectres mettent en kvidence trois structures importantes: deux excitations collectives des 6lectrons de valence e t l'excitation des Blectrons p dn mktal.

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“…The dominant feature in both spectra is the alumina plasmon which shifts from 22.3 eV (no anneal) to 24.8 eV (anneal at 1000 ± C) due to the increase in electron density with crystallization. 16 The volume titania 17 and alumina plasmons are in the same energy range, but the titania peak is much weaker than the alumina peak in the composite spectrum because of the small volume fraction ratio of the titania islands relative to the alumina substrate The low energy titania spectrum was obtained by subtracting the substrate spectrum from the composite spectrum with the relative weight of the two spectra chosen to minimize the peak at 25 eV in the subtracted spectrum. The subtracted spectrum is in error at high energy because multiple scattering contributions are not reproduced correctly by this procedure and because we are oversubtracting the substrate spectrum since the volume plasmon for titania overlaps the alumina plasmon.…”

Section: Electron Energy-loss Resultsmentioning

confidence: 99%

“…The spectrum for rutile is in agreement with transmission EELS measurements by Frandon et al on a 400Å 21 thick, polycrystalline rutile film. 17 The absorption edges for all three materials were fit well by the Tauc model [intensity~(E 2 E g ) 2 ] and the derived gaps were 3.34 6 0.03 eV, 3.11 6 0.08 eV, and 2.71 6 0.13 eV for amorphous titania, anatase, and rutile, respectively. The difference between the Tauc 19 The optical gap for amorphous titania has not been reported previously, and these measurements indicate that it is larger than the rutile and anatase optical gaps.…”

Section: Electron Energy-loss Resultsmentioning

confidence: 99%

Electron energy-loss study of titania particles

Gonzalez

Ritter

1998

J. Mater. Res.

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Small titania particles, prepared by hydrolysis and condensation using in situ steric stabilization, have been studied by high-energy, transmission, electron energy-loss spectroscopy. Electron diffraction patterns and energy-loss spectra as a function of momentum transfer were measured for as-prepared particles (amorphous titania), particles annealed at 600 ± C (primarily anatase), and particles annealed at 1000 ± C (primarily rutile). The energy-loss spectra at low momentum disagreed with the loss function calculated from optical data (rutile) and disagreed with theory (rutile and anatase). The data was fit by an Elliot-like model for a resonant exciton interacting with a continuum of levels. The translational effective mass of the exciton derived from the fitting was quite large, indicating that it was self-trapped.

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Excitations électroniques dans TiO2 rutile et TiO mesure des pertes d'énergie des électrons entre 3 et 60 eV

Cited by 22 publications

References 39 publications

Dielectric Properties of Ti, TiO2 and TiN from 1.5 to 60 eV Determined by Reflection Electron Energy Loss Spectroscopy (REELS) and Ellipsometry

Dielectric Properties of Ti, TiO2 and TiN from 1.5 to 60 eV Determined by Reflection Electron Energy Loss Spectroscopy (REELS) and Ellipsometry

Electronic Excitations in Some Transition Metals and Their Oxides. Characteristic Energy Loss Measurements up to 50 eV

Electron energy-loss study of titania particles

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