In order to determine if electroluminescence(EL) of metal/nanosize Si particle embedded dielectric film/Si structures originate from luminescence centers in silicon oxide or from nanosize Si particles, a comparative study of EL from the Au/nanosize Si particle embedded silicon oxide film/p-Si structures and that from the Au/nanosize Ge particle embedded silicon oxide film/p-Si structures has been carried out. The EL spectra from the two types of structure annealed at the same temperature are very similar to each other. Their dominant EL peaks at around 640 nm shift in the same way, and their EL shoulders at around 510 nm remain invariant, with annealing temperature or with forward bias. Such striking similarities are very difficult to explain if the origin of EL is attributed to nanosize Si particles or nanosize Ge particles, but can be reasonably explained if the origin of EL is attributed to the luminescence centers in the silicon oxide films.