A study was made of the surface modification of porous material by using annealing and rapid oxidation steps. Upon comparing new results with published data, it was concluded that H passivation of the surface was not unique in its ability to saturate dangling bonds and thus promote strong luminescence. Oxidation, especially at high temperatures, could play a similar role. Such oxidation also produced an additional low-energy band which was linked to residual dangling bond related defects at the Si/SiO2 interface. This band underwent a blue shift, with increasing porosity, in a similar fashion to that which was observed for visible emissions.

S.Gardelis, B.Hamilton: Journal of Applied Physics, 1994, 76[9], 5327-33