MICROSTRUCTURE AND ATOMIC EFFECTS ON THE ELECTROLUMINESCENT EFFICIENCY OF SRS-CE THIN-FILM DEVICES

Transmission electron microscopy and x-ray diffraction data show that rapid thermal anneals of SrS:Ce thin films enhance grain size and redu ce crystalline defects. Electron paramagnetic resonance results sugges t that these anneals lead to less variance in the crystal field enviro nments at the nearly cubic Ce3+ sites along with the formation of anot her type of Ce3+ sire believed to involve a nearby Sr vacancy. We sugg est that the association of Ce3+ sites with V-Sr shifts the electrolum inescence towards larger wavelengths as the symmetry of the activator sire is lowered. (C) 1997 American Institute of Physics.