CATHODOLUMINESCENCE EMISSION-SPECTRA OF ND-DOPED CAF2

Rare-earth doping of CaF2 results in material which exhibits significa nt cathodoluminescence (CL) signals. Therefore CL measurements made on CaF2:Nd are reported for the temperature range 50 to 300 K with diffe rent excitation modulation frequencies. Since annealing treatment can be used to modify the spectra, the effects of annealing treatments of CaF2:Nd have been examined. Dopant levels used in the present study ar e 1.0, 0.1, and 0.01% Nd. All dopant levels exhibited different CL spe ctra with a combination of broad emission bands from the CaF2 host and lines from the Nd dopants. Broad bands are centred near 340 and 645 n m. The intense emission lines at 360, 389, and 419 are assigned D-4(3/ 2) to I-4(j) (j = 9/2 and 11/2) and P-2(1/2) to I-4(9/2), respectively . Other transitions to Nd transitions from 4D from D-4(3/2), (4)G(9/2) , (4)G(5/2) and (4)G(5/2), (2)G(7/2) to I-4(j) (j = 9/2 to 15/2) are f ound. The 340 nm band is associated with the intrinsic emission, self- trapped exciton (STE) emission, of CaF2. The temperature dependence of the intensity of the emission band is discussed. The intrinsic emissi on band intensities decrease with increasing Nd content.