Abstract— Fully combined metal-oxide-semiconductor compat- ible light-emitting devices based on nano bi-layer structures are fabricated. The active layers are composed of silicon nitride on top of a silicon-enriched silicon dioxide film with different Si concentrations. Electro and photo luminescence spectra of the devices and the active materials are analyzed and correlated to verify if the origin of the emission is the same. Differences found between electrically and optically stimulated photo-emission in the studied region of the spectra are concluded to be due to optical phenomena introduced by the gate and multilayer configuration, meaning that the same radiative centers are stimulated optically and electrically.