Optical properties of Ce-doped SiO2 films: From isolated Ce3+ ions to formation of cerium silicate

Weimmerskirch-Aubatin, Jennifer; Stoffel, M.; Bouché, A; Boulet, Pascal; Vergnat, M.; Rinnert, H.

doi:10.1016/j.jallcom.2014.10.057

Cited by 14 publications

(13 citation statements)

References 23 publications

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“…For the sample annealed at 1100 C, the mean composition of the Ce-rich clusters is X Ce ¼ 16. 3 8,9,22 Moreover, the measured composition shows first an increase of the Si content with a constant Ce composition ($ 7%-8%) between as-deposited and 900 C annealing (in agreement with Figure 2(b)). Annealing at 980 C leads to a Ce enrichment while the Si content decreases (Figure 2(c)).…”

Section: Resultssupporting

confidence: 86%

Structural and optical study of Ce segregation in Ce-doped SiO1.5 thin films

Beainy

Weimmerskirch-Aubatin

Stoffel

et al. 2015

Journal of Applied Physics

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Cerium doped SiO 1.5 thin films fabricated by evaporation and containing silicon nanocrystals were investigated by atom probe tomography. The effect of post-growth annealing treatment has been systematically studied to correlate the structural properties obtained by atom probe tomography to the optical properties measured by photoluminescence spectroscopy. The atom probe results demonstrated the formation of Ce-Si rich clusters upon annealing at 900 C which leads to a drastic decrease of the Ce-related luminescence. At 1100 C, pure Si nanocrystals and optically active cerium silicate compounds are formed. Consequently, the Ce-related luminescence is found to re-appear at this temperature while no Si-nanocrystal related luminescence is observed for films containing more than 3% Ce. V C 2015 AIP Publishing LLC. [http://dx.

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Section: Resultssupporting

confidence: 86%

Structural and optical study of Ce segregation in Ce-doped SiO1.5 thin films

Beainy

Weimmerskirch-Aubatin

Stoffel

et al. 2015

Journal of Applied Physics

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“…The luminescence was attributed to the formation of Ce-silicates. Similar observations were made in other studies [17,20,21].…”

Section: Introductionsupporting

confidence: 92%

Correlation between the nanoscale structure and the optical properties of Ce-doped SiO 1.5 thin films

Beainy

Weimmerskirch-Aubatin

Stoffel

et al. 2017

Journal of Luminescence

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Cerium doped SiO x (0 ox o 2) thin films have emerged as promising materials for future Si-based blue light emitting devices. The optical properties of these films are strongly dependent on the nanoscale structure such as the spatial distribution of the Ce atoms. These issues have remained difficult to observe in practice by conventional techniques. In this work, we propose to use atom probe tomography which has emerged as a unique technique that is able to provide information about the chemical composition of the films together with a 3D map indicating the position of each atom from a specimen. Ce-doped SiO 1.5 thin films fabricated by evaporation were investigated. The effect of Ce-content has been systematically studied in order to correlate the structure at the nanoscale with the optical properties measured by photoluminescence spectroscopy.

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“…With the pumping energy being resonant with the UV absorption band of Ce 3+ ions, a direct excitation from the fundamental level 2 F5/2 up to the 5d states is expected to dominate, regardless of the nitrogen content. 51 For Tb 3+ ions however, no absorption bands are located at the pumping energy, 52 and thus, indirect excitation is expected. Indeed, if we recall how the nitrogen incorporation modifies the measured energy bandgap of samples (see figure 2(c)), we find a range from ~ 4.2 eV for nitrogen-free SiO2 hosts down to ~ 3.6 eV for a nitrogen content of 42 at.…”

Section: Photoluminescencementioning

confidence: 99%

“…with previously reported works. 51 Therefore, the emergence of the PL emission from either Tb 3+ -or Ce 3+ -doped films at high annealing temperatures can be attributed to the formation of RE silicates. Such nanocrystallites provide an ideal trivalent bonding for RE ions, which are evenly distributed within the crystal.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

Luminescence properties of Ce3+ and Tb3+ co-doped SiOxNy thin films: Prospects for color tunability in silicon-based hosts

Ramírez

Ruiz‐Caridad

Wójcik

et al. 2016

Journal of Applied Physics

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In this work, the role of the nitrogen content, the annealing temperature and the sample morphology on the luminescence properties of Ce 3+ and Tb 3+ co-doped SiOxNy thin films has been investigated. An increasing nitrogen atomic percentage has been incorporated in the host matrix by gradually replacing oxygen by nitrogen during fabrication while maintaining the Si content unaltered, obtaining a sequential variation in the film composition from nearly stoichiometric SiO2 to SiOxNy. The study of rare earth doped single layers has allowed us to identify the parameters that yield an optimum optical performance from Ce 3+ and Tb 3+ ions. Ce 3+ ions proved to be highly sensitive to the annealing temperature and the nitrogen content, showing strong PL emission for relatively low nitrogen contents (from 0 to 20 %) and moderate annealing temperatures (800-1000 °C) or under high temperature annealing (1180 °C). Tb 3+ ions, on the other hand, displayed a mild dependence on those film parameters. Rare earth co-doping has also been investigated by comparing the luminescence properties of three different approaches: (i) a Ce 3+-and Tb 3+ co-doped SiOxNy single layer, (ii) a bilayer composed of two SiOxNy single layers doped with either Ce 3+ or Tb 3+ ions, and (iii) a multilayer composed of a series of either Tb 3+ or Ce 3+-doped SiOxNy thin films with interleaved SiO2 spacers. Bright green emission and efficient energy transfer from either Ce 3+ ions or Ce silicates to Tb 3+ ions has been observed in the co-doped single layer as a consequence of the strong ion-ion interaction. On the other hand, independent luminescence from Ce 3+ and Tb 3+ ions has been observed in the Ce 3+ and Tb 3+ co-doped bilayer and multilayer, providing a good scenario to develop light emitting devices with wide color tunability by varying the number of deposited films that contain each rare earth dopant. Moreover, the optoelectronic properties of Ce 3+-and/or Tb 3+-doped thin films have been studied by depositing transparent conductive electrodes over selected samples. An electroluminescence signal according to the rare earth transitions is obtained in all cases, validating the excitation of Ce 3+ and Tb 3+ ions upon electron injection. Also, the main charge transport of injected electrons has been evaluated and correlated with the layer stoichiometry. Finally, a simple 2 reliability test has allowed disclosing the origin of the early breakdown of test devices, attributed to the excessive joule heating at filament currents that occur around a region close to the polarization point.

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Optical properties of Ce-doped SiO2 films: From isolated Ce3+ ions to formation of cerium silicate

Cited by 14 publications

References 23 publications

Structural and optical study of Ce segregation in Ce-doped SiO1.5 thin films

Structural and optical study of Ce segregation in Ce-doped SiO1.5 thin films

Correlation between the nanoscale structure and the optical properties of Ce-doped SiO 1.5 thin films

Luminescence properties of Ce3+ and Tb3+ co-doped SiOxNy thin films: Prospects for color tunability in silicon-based hosts

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