Tunable and stable UV-NIR photoluminescence from annealed SiOx with Si nanoparticles.

We demonstrate stable and tunable light emission in ultraviolet to near infrared regime by using annealed SiOx sample. By adjusting the ratio of Si and O of SiOx, different wavelengths such as ultraviolet, visible and near infrared photoluminescence can be tuned. From the results of transmission electron microscope, various sizes (1~4 nm) of the embedded Si nanoparticles were formed. Nanoparticles with smaller sizes were indeed formed for UV-blue emitting samples and the origin of light emission may be misattributed to the quantum confinement effects. However, we found the efficient and stable light emission in UV-blue regime, with lifetime on the order of nanoseconds, is dominantly from the defects.