Eu luminescence from BaTiO3/SiO2 multilayer xerogel structures

Abstract

Sol–gel technology was applied to fabricate Eu-doped BaTiO3/SiO2 multilayer structures by spinning on silicon and fused silica substrates. Eu photoluminescence (PL) was investigated depending on the annealing temperature of these structures. The samples demonstrate the room temperature luminescence corresponding to 5D0 ! 7FJ (J ¼1, 2, 3, 4) transitions of trivalent europium with the most intensive band at 615 nm. For the structure on fused silica with Eu in the BaTiO3 cavity, increase of the annealing temperature from450○C to 700○C resultsinmodification of the luminescence indicatrixandloweringof the luminescence intensity in the direction along the surface normal. For BaTiO3/SiO2 multilayer structure generated on silicon, scanning electron microscopy (SEM) analyses reveal disordering after annealing at 1000○C. This heat treatment provides also an increase of the Eu luminescence intensity.