Visible Light Emission from SiO x Films Synthesized by Laser Ablation

We have developed a method for synthesizing SiO x films with visible light emission, applying a laser ablation technique. The films were formed by depositing laser-ablated silicon particles in oxygen gas diluted with helium gas. Soft X-ray absorption spectroscopy revealed that the composition of the film is controlled by the total pressure of the gas. Films with particular composition exhibit intense red photoluminescence with a peak below 1.5 eV after annealing in argon gas at 1000°C. In addition to this, most of the films exhibit 2.2-eV photoluminescence after annealing at 500°C. On the basis of these results, the origin of the photoluminescence is discussed.