It was recalled that, because the bulk material did not emit visible light, the observation of visible luminescence from porous material had generated great interest. The porous material differed from bulk Si in that it consisted of interconnected Si nanostructures with very large surface/volume ratios. The first emission mechanism which had been proposed involved carrier recombination within quantum-sized Si particles, but more recent work had shown that surface emission was more likely. Here, an interfacial O center luminescence model was considered with regard to the experimental data. It was suggested that there was a direct correlation between the presence of these centers and the red photoluminescence of both as-prepared and oxidized porous Si.

S.M.Prokes, W.E.Carlos: Materials Science Forum, 1995, 196-201, 1679-82