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Cerium doped SiO1.5 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. [ABSTRACT FROM AUTHOR]

Er-doped silica or rich-silicon oxide has been widely studied as 1.54 μm emitters. The incorporation of Si-nanoclusters is known for improving luminescence yield of Er 3+ ions through an efficient sensitization of the neighboring rare earth ions. The aim of this work is to investigate the influence of Silicon excess and Erbium concentration on the formation of silicon nanoclusters and Er-rich phase responsible of the quenching of 1.54 μm emission. Atom probe tomography and photoluminescence spectroscopy were used to explore the nanostructure and optical activity of Er-doped silicon rich silica. We present a direct evidence that both silicon excess and Er concentration influence the growth of Si nanoclusters, the formation of Er-Si-O phase and the luminescence of both Si nanoclusters and Er 3+ ions. We explain these finding in relation with the growth mechanism of nanoparticles and the presence of a Snowman-like Janus morphology between silicon and Erbium silicates nanoparticles. In this contribution, we deciphered the nanoscale structure spatial correlations between Er and Si atoms in Er doped SiO X which remained unclear for a long time. [ABSTRACT FROM AUTHOR]

We report on the effect of annealing treatment on the structural and optical properties of Er-doped Al 2 O 3 thin films elaborated by atomic layer deposition. The properties of the films were studied using ellipsometry and Fourier-transform infrared (FTIR) spectroscopies, cathodoluminescence (CL) versus annealing temperature varied in the 650-1100 °C range. Spatial location and diffusion of chemical species were investigated at the atomic scale by atom probe tomography (APT). The CL measurements evidence Er 3 + light emission over the visible-infrared spectral range. The CL spectra evolution showed non-monotonic variation with annealing temperature and a CL quenching occurring at 1000 °C. The CL signal evolution as a function of the annealing treatment is discussed regarding to the evolution of structural properties. • ALD allows high and homogeneous Er incorporation in Al 2 O 3. • Characterizations were performed using Ellipsometry, FTIR, CL and APT. • Annealing temperature enables the control of amorphous or crystalline Al 2 O 3. • High Er 3 + cathodoluminescence is observed in amorphous or crystalline Al 2 O 3. • The correlation between luminescence and structure is discussed. [ABSTRACT FROM AUTHOR]

The optical and structural properties of Er-doped Silicon oxide based thin films elaborated by RF magnetron sputtering were investigated as a function of annealing treatment. Atom Probe Tomography and Transmission electron microscopy were used to analyze the position of rare-earth ions as well as the phase separation occurring in the layer in order to provide a complete picture of the nanostructure. The emission properties of Er3+ ions were investigated using cathodoluminescence (CL) spectroscopy. The high doping level of Er ions in silicon oxide matrix leads to a phase decomposition of pure SiO 2 and Er 2 Si 2 O 7 phases with a nanostructure which is influenced by the annealing treatment. It results on different emission intensities in ultraviolet or infrared ranges. The relationship between the nanostructuration observed and the optical properties is discussed in regards of annealing treatment. [Display omitted] • The rare earth pyrosilicate B-Er 2 Si 2 O 7 ceramic was fabricated by magnetron sputtering • High Er3+ cathodoluminescence is observed in amorphous or crystalline Er 2 Si 2 O 7 phase. • The correlation between cathodoluminescence and structrure of Er 2 Si 2 O 7 phase in silica matrix is discussed. [ABSTRACT FROM AUTHOR]

Luminescence and structural properties of Pr3+ doped HfSiO x thin layer elaborated by magnetron sputtering have been investigated as a function of the annealing temperature. The emission properties of Pr3+ ions were studied using photoluminescence (PL) and cathodoluminescence (CL) spectroscopies. Phase separation between amorphous SiO 2 and crystallized HfO 2 nano-grains occurring in the HfSiO x matrix has been investigated by atom probe tomography and transmission electron microscopy with particular consideration for the Pr distribution. Both PL and CL measurements evidenced a strong emission originating from Pr3+ ions in the visible range for an annealing temperature higher than 950°C. At 950°C, Pr3+ ions are clearly located in HfO 2 nano-grains of cubic structure. Regarding PL, no significant changes are observed between 950°C and 1050°C. However, CL measurements revealed new emission peaks in the infrared range after an annealing at 1050°C, corresponding to the appearance of a new orthorhombic crystalline structure of HfO 2 nano-grains in the thin layer. The CL signal evolution as a function of the annealing treatment is discussed in regard to the evolution of structural properties. [Display omitted] • Pr3+ doped HfSiO x , annealed at 950°C, exhibited strong cathodoluminescence and photoluminescence properties in visible range. • Near infrared cathodoluminescence signal of Pr3+ is observed at 1050°C. • HfSiO x matrix dissociates into mixed amorphous SiO 2 and crystalline HfO 2 phases. • The correlation between cathodoluminescence and the crystalline structure of Pr3+ doped HfSiO x is discussed. [ABSTRACT FROM AUTHOR]