Photoluminescence and Photoluminescence Excitation Measurements of Eu-doped nano-Si/SiO_2 Thin Films

摘要

We synthesized thin films of RF co-sputtered Eu_2O_3, Si and SiO_2 on quartz substrates. Previous time domain PL measurements and four-wave mixing measurements of samples, with and without Eu, gave evidence that is consistent with a possible transfer of electrons from Si nanoparticles to Eu~(3+) ions, resulting in photo-induced transient Eu~(2+) states responsible for an observed whitish PL. We report on PLE measures that let us determine that Eu~(2+) is actually present in the samples, at least during the illumination of the samples, and transmission measurements giving evidence that it coexists with nanoparticles of Si. Meanwhile, Eu~(3+) is also present in some of the samples. If this proposed interaction is confirmed, it has potential for applications in light emitting devices and screens, as well as in sensors. We have already found some success applying this hardy material to Si light sensors, to enhance their sensitivity in the UV range.