Electroluminescence (EL) spectra under direct-current (de) operation are reported for Au/SiO2/p-Si MOS capacitors with 50 nm Si-implanted SiO2. The transparent Au gate not only improves measurable wavelength range but also suppresses interference effects among MOS layers. The clear and smooth EL spectra have been measured and the EL spectrum was analyzed by fitting five Gaussian distribution functions. A model of EL emission mechanism is proposed for the Si-implanted MOS EL device. Furthermore, photomicrograph of blue EL emission is given, and a possibility of visible light emitting microdisplay device is demonstrated. (C) 2004 Elsevier Ltd. All rights reserved.