Ultraviolet luminescence of Li6Gd(BO3)(3): Ce crystals under selective excitation in the region of 4d -> 4f transitions

The subnanosecond time-resolved ultraviolet luminescence of Li 6Gd(BO 3) 3: Ce crystals under selective excitation by ultrasoft X-rays in the region of the 4d→4f core transitions at temperatures of 7 and 293 K has been investigated for the first time. The performed investigation has revealed the following features: an intense fast component of the luminescence decay kinetics in the subnanosecond range due to the high local density of electronic excitations and the processes of Auger relaxation of the core hole; the modulation of the luminescence excitation spectrum by the "giant resonance" absorption band of the 4d-4f photoionization in the energy range 135-160 eV; and a new broad luminescence band at an energy of 4.44 eV due to the direct radiative recombination between the genetically related electron in the states of the conduction band bottom and hole in the 4f ground state of the Ce 3+ ion. © 2012 Pleiades Publishing, Ltd