DC electroluminescence efficiency of silicon rich silicon oxide light emitting capacitors

We analyze the influence of the fabrication technique and the silicon excess on the power efficiency and evolution with time of the electroluminescence of silicon rich silicon oxide in metal-oxide-semiconductor like light emitting capacitors under direct current. The silicon rich silicon oxide layers have been fabricated using two different techniques, namely plasma enhanced chemical vapor deposition and silicon ion implantation. Six different silicon excesses have been studied, ranging from 6 at. % to 15 at. %. It is shown that both the power efficiency and external quantum efficiency increase with the silicon excess due to a decrease in the electroluminescence current threshold. The maximum value of the power efficiency has been found to be (2.6 ± 0.3) × 10^-5 in the ion implanted sample with 15 at. % silicon excess. Significant differences in the evolution of the electroluminescence with time are found depending on the fabrication technique.