Premium
The processing and characterization of CaGa 2 S 4 :Ce blue phosphor by MOCVD
Author(s) -
Moss T. S.,
Smith D. C.,
Samuels J. A.,
Dye R. C.,
DelaRosa M. J.,
Schaus C. F.
Publication year - 1997
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1889/1.1985137
Subject(s) - deposition (geology) , metalorganic vapour phase epitaxy , caga , phosphor , electroluminescence , materials science , analytical chemistry (journal) , chemistry , epitaxy , nanotechnology , layer (electronics) , optoelectronics , environmental chemistry , geology , paleontology , biochemistry , sediment , virulence , gene
Abstract— The deposition of CaS, Ga 2 S 3 , and CaGa 2 S 4 :Ce has been accomplished by MOCVD using Ca(tmhd) 2 , Ga(tmhd) 3 , and Ce(tmhd) 4 , with a liquid delivery system to control the flows. Samples were primarily characterized using x‐ray fluorescence and electroluminescence measurements of the color and luminance. Analysis shows the CaS deposition is mass‐transport limited, while the Ga 2 S 3 is limited by the deposition kinetics. However, application of these mechanisms to the CaGa 2 S 4 :Ce deposition system reveals that the CaGa 2 S 4 :Ce is independent of its components. Further, the deposition of CaGa 2 S 4 :Ce is found to be Ca‐rich under conditions which lead to low Ga/Ca ratios in the deposited film. This indicates that the conversion of Ca from Ca(tmhd) 2 was catalyzed by the slight presence of Ga in the form of CaGa 2 S 4 :Ce or Ga 2 S 3 on the surface. The Ca is thought to be deposited as CaS: Ce, since there is a shift in the EL color towards green under low Ga/Ca ratios. The Ca conversion is found to approach values predicted by the CaS deposition mechanism under conditions which lead to high Ga/Ca ratios, implying that excess Ga 2 S 3 is needed for the deposition of CaGa 2 S 4 :Ce without any CaS:Ce inclusions.