Stabilization of porous silicon electroluminescence by surface capping with silicon dioxide films

摘要

To prolong the operation life of electroluminescence (EL) from porous silicon (PS) diodes without affect on the efficiency, the surface passivation technique is applied to the active PS layer. By combining a postanodization electrochemical oxidation (ECO) technique for the PS layer with a surface capping by SiO{sub}2 films sputtered using electron cyclotron resonance (ECR) method, the degradation of the EL efficiency is effectively suppressed for a long time over several hours under a ew operation. It is shown that from thermal desorption spectra analyses, the capability of capped films as a barrier against penetration of water molecules is a key factor for stabilizing the EL operation due to preventing luminescent PS layers from current-induced oxidation.