Photoluminescence properties of europium-doped porous silicon nanocomposites

We present new results concerning the photoluminescence properties of europium (Eu3+) incorporated in porous silicon (PS) matrix. Eu3+ ions were embedded in the matrix by simple impregnation of PS layers in chloride solution of europium. Complete and uniform penetration of Eu3+ into the pores is proved from RBS study. The PL spectrum shows the existence of several peaks superposed to the PL band of PS. These peaks are related to level transitions in Eu3+. The effect of the ray excitation on the PL shows that energy transfer is not the principal route for radiative recombination. A systematic study of the PL versus annealing temperature was performed. It was found that the optimised PL spectrum is found after annealing at 1000°C. Low-temperature study of the PL shows an important increase of the intensity and a broadness of the peaks due to the appearance of a second crystallographic site.