Stabilization of electroluminescence and photoluminescence of porous n-silicon by chemical oxidation in H2O2

ABSTRACTWe have oxidized porous (n-)silicon samples in solutions of H202 and have found that PL can be stabilized at a high level. The PL intensity of as prepared samples (PL quantum efficiencies in the range of 5 %) degrades to about 1/3 of the initial value in some ten minutes (the exact value depends on the experimental conditions). After having treated the samples for about 30 - 45 minutes in hydrogen peroxide it can be observed that bright PL remains stable for hours. These results confirm similar experiments performed with porous silicon made from p-substrates1. While red electroluminescing samples have shown long time stability for about 100 hours2, samples with blue-green electroluminescence have a lifetime of about 20 - 40 minutes. Oxidizing electroluminescent samples as described above results in a stabilization of electroluminescence for more than 7 hours.