Light emission from porous silicon prepared using metal-dissolved hydrofluoricsolution

Abstract

In this work we report on the photoluminescence (PL) characteristics of porous silicon (PS)prepared by electrochemical anodization of a p-type Si wafer using chemicallymetal-dissolved hydrofluoric solutions. Various solid metals, oxidative (Al, Fe, Sn, Ni, Cr)and reductive (Cu), were used for this work. The effects of metals on the PL properties inas-grown, illuminated, and aged states have been studied. It is found that for the as-grownstate the PL intensity is reduced by the addition of metal. In particular, the Cu-doped PSreveals a PL intensity lower by one order of magnitude as compared to that of normal PS.The improvement of stability in the PL intensity under illumination was onlyobserved for the Cu-doped PS sample, which is more stable by a factor of 2 ascompared to that of normal PS. On the other hand, the improved stability of the PLintensity in the aged state was observed for metal-doped PS samples other than forthe Cu-doped sample. From the results, it is suggested that reductive metalsare more effective in reducing the PL degradation caused by illumination whileoxidative metals are more effective in reducing the PL degradation caused by ageing.