The Photoluminescence from (Eu, Yb) Co-Doped Silicon-Rich Si Oxides

We report on photoluminescence (PL) properties of europium (Eu) and ytterbium (Yb) co-doped silicon oxide films with different Si excess. After annealing the films in N2, strong PL were observed from Eu and Yb3+ ions and their intensities are correlated. The PL intensity of Eu is mainly from 3+ for no and relatively low temperature anneals (°C) while the Eu2+ emission is dominating for annealing at 1000 °C or above in the co-doped Si-rich oxide films. Transmission electron microscopy shows amorphous (Eu, Yb, Si, O)-containing precipitates in the Si-rich oxide during 1000-1200 °C annealing and these precipitates are considered to be responsible for the Eu2+-related luminescence.