CATHODOLUMINESCENCE OF CELA2BE2O5 SINGLE-CRYSTALS

Ce3+:Y3Al5O12 (Ce:YAG) is an important phosphor in high intensity CRT displays since it does not saturate at high electron beam power. The s aturation power level is of the order of 1 W/cm2 for most cathodolumin escent materials, and this limits the maximum surface brightness of a typical cathode ray tube. However, Ce3+:YAG has been found to be linea r to at least 10(4)W/cm2. This performance has encouraged our examinat ion of another cerium activated phosphor, lanthanum beryllate, Ce:La2B e2O5 (Ce:BEL). A crystal of lanthanum beryllate activated with a ceriu m concentration of 410(18) atoms/cm3 was grown by the Czochralski crys tal growth technique. Wafers were prepared from the crystal and analyz ed in both the as-grown state and after annealing in a flowing atmosph ere of 10% by volume hydrogen in argon at 1150-degrees-C for 4 h. Cath odoluminescent measurements revealed a broadband blue emission of 100 nm width centered at 480 nm, a blue-shifted analog of the Ce:YAG spect rum. A linear efficiency of 0.13 lm/W was found to a power loading of 8 W/cm. Pulsed excitation of a Ce:BEL crystal by 375 nm radiation prod uced by frequency doubling of a 750 nm laser demonstrated a decay time of the fluorescence of the order of 50 ns. All these data show that C e:La2Be2O5 is an excellent candidate as a blue phosphor for high inten sity CRT applications, particularly for high resolution projection dis plays using single crystal faceplates.