Metal-oxide-silicon-based light-emitting diodes with Gd-implanted SiO2 layers exhibit strong ultraviolet electroluminescence at 316 nm coming from Gd3+ ions. Co-implantation of potassium ions into the SiO2: Gd layer leads to elimination of the luminescent peak from point defects in SiO2 layers. The electropositive potassium ions compensate the negative charge trapping in the gate oxide and thus improve the electrical stability of the ultraviolet emission from Gd3+ ions. The operating time of the devices was increased more than 30 times by using potassium co-implantation and millisecond flash lamp annealing. (c) 2006 The Electrochemical Society.