Effects of annealing treatments on the photoluminescence decay properties of Si-rich oxide/SiO2 multilayer films

•Si-rich oxide (SRO)/SiO2 multilayer films with different annealing temperatures are obtained.•Time-resolved PL spectra are well fitted by a multiexponential PL decay model.•Two lifetime distribution bands are obtained after the formation of crystallized Si-QDs. In this work, Si-rich oxide (SRO)/SiO2 multilayer films have been deposited and the photoluminescence (PL) decay properties of the films with different annealing temperatures are studied. The PL shifts toward low energy with increasing the annealing temperature, and intense PL at around 1.4eV is obtained after annealing at 1100°C. The PL decay curves can be well fitted by a multiexponential PL decay model, and the peak of the PL lifetime distribution band shifts toward longer time with increasing the annealing temperature. Two lifetime distribution bands are obtained after the formation of crystallized Si-QDs, and the proportion of slow component increases from 69.72% to 77.04% after hydrogen passivation. Analyses show that defect states recombination in the SRO layer is the main optical emission mechanism when the annealing temperature is lower than 900°C, and interband transition in the Si-QDs due to quantum confinement effect is the main PL mechanism when the film is annealing at 1100°C.