Observation of a nanoscale phase separation in blue-emitting Ce-doped SiO1.5 thin films. Issue 48 (24th November 2015)

• Record Type: Journal Article
• Authors: Weimmerskirch-Aubatin, J.; Stoffel, M.; Devaux, X.; Bouché, A.; Beainy, G.; Talbot, E.; Pareige, P.; Fagot-Révurat, Y.; Vergnat, M.; Rinnert, H.
• Is Part Of: Journal of materials chemistry. Volume 3:Issue 48(2015)
• Page Start: 12499
• Page End: 12506
• Publication Date: 2015-11-24
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c5tc02722e
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : The observation of a phase separation at the nanoscale between pure Si nanocrystals and Cerium silicate clusters is reported. Abstract : Both the optical and structural properties of Ce-doped SiO1.5 thin films were investigated. The Ce-related blue luminescence, which can be seen even at room temperature for as-grown films, exhibits a rather complex evolution with the annealing temperature. In particular, a strong decrease is observed when the films are annealed at 900 °C. Structural characterizations combining scanning transmission electron microscopy and atom probe tomography reveal the formation of Si- and Ce-rich clusters at this temperature, thus demonstrating that the decreasing Ce-related luminescence is due to concentration induced quenching. For annealing temperatures higher than 900 °C, the Ce-related luminescence increases. The different structural characterizations provide clear experimental evidence of a phase separation occurring at the nanoscale between pure Si nanocrystals and Ce-rich clusters having a stoichiometry close to the cerium silicates Ce2 Si2 O7 or Ce4.667 (SiO4 )3 O. The latter compounds are optically active thereby explaining the increased Ce-related luminescence observed at the highest annealing temperature.