PHOTOLUMINESCENCE AND PHOTOLUMINESCENCE EXCITATION MEASUREMENTS OF Eu-DOPED NANO-Si/SiO2 THIN FILMS
G. A. NERY*, L. F. FONSECA, H. LIU**, O. RESTO, S. Z. WEISZ
UNIVERSITY OF PUERTO RICO AT RIO PIEDRAS, PR
Keywords: EUROPIUM, PL, PLE, PHOTOLUMINESCENCE, EXCITATION, NANOPARTICLE, SILICON, SILICON DIOXIDE, EU, SI, SIO2
Europium (Eu) ions are already used in significant visual technological applications. We attempted to determine if a silicon nanoparticle (nano-Si) / Europium interaction could occur. The energy transfer from nano-Si to rare earth ions has already been documented for Erbium. Such an event, in the case of Europium, could help it to increase its light emission efficiency for use in devices.
We synthesized thin films of RF co-sputtered Eu2O3, Si and SiO2 on quartz substrates. Previous time domain PL measurements and four-wave mixing measurements of samples, with and without Eu, gave some evidence that is consistent with a possible transfer of an electron from Si nanoparticles to Eu3+ ions, resulting in a photo-induced transient Eu2+ state responsible for the whitish PL . The new set of samples were prepared for the present PL and PLE measurements in order to determine whether or not Eu2+ is actually present in the samples, and also to recheck for the presence of Eu3+ .
A comparison of the results of these measurements with results in similar materials shows that there is actually Eu2+ present in the samples, at least during the illumination of the samples, and that Eu3+ is also present in the samples.
If this proposed interaction is confirmed, it has potential for applications in light emitting devices and screens, as well as in sensors. In fact, we have already found some success applying this hardy material to light sensors .
NSTI Nanotech 2003 Conference Technical Program Abstract