Modulation of the 1535 nm photoluminescence from Er-doped Si-rich silicon dioxide by field-induced quenching

Field-induced quenching of the efficient photoluminescence at 1535 nm was observed from Si-rich SiO2:Er thin films prepared by Er and Si co-implantation. The quenching effect was strongly enhanced by increasing the density of silicon nanoclusters at an electric field above 5 MV/cm. A modulation ratio of 0.37 was obtained at an electric field of 9 MV/cm for a 200 nm Er-doped Si-rich layer containing 0.24 % of Er atoms and 10% excess Si nanoclusters. The mechanism of the field-induced quenching of the photoluminescence was studied by simultaneously measuring the light intensity from nanolusters and Er3+ ions, the injection current and the electric field. The quenching mechanism could be attributed to the field induced separation of the excitons created in silicon nanoclusters and tunneling of carriers between the Er ions and silicon nanoclusters. This strong field quenching effect will be useful for controlling the optical gain in a Si-rich SiO2:Er waveguide amplifiers, but also for the small size optical modulator in silicon photonics.