New approaches for enhancing light emission from Er-based materials and devices

Irrera, A., Galli, M., Miritello, M., Lo Savio, R., Iacona, F., Franzò, G., Canino, A., Piro, A.M., Belotti, M., Gerace, D., Politi, A., Liscidini, M., Patrini, M., Sanfilippo, D., Fallica, P.G., Andreani, L.C. and Priolo, F. (2009) New approaches for enhancing light emission from Er-based materials and devices. Physica E: Low-dimensional Systems and Nanostructures, 41 (6), 891-898. (doi:10.1016/j.physe.2008.08.050).

Abstract

In this work, we present some approaches recently developed for enhancing light emission from Er-based materials and devices. We have investigated the luminescence quenching processes limiting quantum efficiency in light-emitting devices based on Si nanoclusters (Si nc) or Er-doped Si nc. It is found that carrier injection, while needed to excite Si nc or Er ions through electron–hole recombination, at the same time produces an efficient non-radiative Auger de-excitation with trapped carriers. A strong light confinement and enhancement of Er emission at 1.54 ?m in planar silicon-on-insulator waveguides containing a thin layer (slot) of SiO2 with Er-doped Si nc at the center of the Si core has been obtained. By measuring the guided photoluminescence from the cleaved edge of the sample, we have observed a more than fivefold enhancement of emission for the transverse magnetic mode over the transverse electric one at room temperature. Slot waveguides have also been integrated with a photonic crystal (PhC), consisting of a triangular lattice of holes. An enhancement by more than two orders of magnitude of the Er near-normal emission is observed when the transition is in resonance with an appropriate mode of the PhC slab. Finally, in order to increase the concentration of excitable Er ions, a completely different approach, based on Er disilicate thin films, has been explored. Under proper annealing conditions crystalline and chemically stable Er2Si2O7 films are obtained; these films exhibit a strong luminescence at 1.54 ?m owing to the efficient reduction of the defect density.

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Contributors

Author: A. Politi

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