title: Synthesis of Sr2Si5N8:Ce3+phosphors for white LEDs via an efficient chemical vapor deposition [corrected].
abstract: Novel chemical vapor deposition (CVD) process was successfully developed for the growth of Sr2Si5N8:Ce3+phosphors with elevated luminescent properties. Metallic strontium was used as a vapor source for producing Sr3N2vapor to react with Si3N4powder via a homogeneous gas-solid reaction. The phosphors prepared via the CVD process showed high crystallinity, homogeneous particle size ranging from 8 to 10 μm, and high luminescence properties. In contrast, the phosphors prepared via the conventional solid-state reaction process exhibited relative low crystallinity, non-uniform particle size in the range of 0.5-5 μm and relatively lower luminescent properties than the phosphors synthesized via the CVD process. Upon the blue light excitation, Sr2-xCexSi5N8phosphors exhibited a broad yellow band. A red shift of the emission band from 535 to 556 nm was observed with the increment in the doping amount of Ce3+ions from x = 0.02 to x = 0.10. The maximum emission was observed at x = 0.06, and the external and internal quantum efficiencies were calculated to be 51% and 71%, respectively. Furthermore, the CVD derived optimum Sr1.94Ce0.06Si5N8phosphor exhibited sufficient thermal stability for blue-LEDs and the activation energy was calculated to be 0.33 eV. The results demonstrate a potential synthesis process for nitride phosphors suitable for light emitting diodes.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Che-Yuan
authors.initials: CY
authors.lastname: Yang
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Som
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Subrata
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Chung-Hsin
authors.initials: CH
authors.lastname: Lu