The photoluminescence and structural properties of (Ce, Yb) co-doped silicon oxides after high temperature annealing

We studied the photoluminescence (PL) and structural properties of Ce and Yb co-doped silicon oxide films after high temperature annealing. The PL spectra of Ce³⁺ and Yb³⁺ ions were sensitive to the structural variation of the films, and the Yb PL intensities were significantly enhanced especially upon 1200 °C annealing. X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy, indicated that rare earth silicates and the CeO₂ phase had formed in the oxides. The proportions of the phases varied with the "nominal Si-richness" of the films. Energy transfer from the excited Ce³⁺ to Yb³⁺ can be inferred from both PL excitation and decay spectra.