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After the treatment of porous Si by "amine immersion and rapid thermal oxidation", the peak position of the photoluminescence spectra has a blue shift to 500nm. Only a little change in photoluminescence was observed after 160d storing in dry air. FTIR spectra indicate that the compositions of such treated sample are mainly silicon and oxygen. ESR signal shows that the blue/green light-emitting sample has rather low density of dangling bonds. These results demonstrete that the quantum confinement effect and surface states play a key role in blue/green light emitting. This method is simple and practicable, to make blue/green light-emitting samples and its success ratio can achieve 70%.

Porous silicon is treated in NH3 gas by rapid thermal annealing. FTIR spectra indicate that the surface of the sample is covered with Si(NH)2 and Si3N4 species. ESR signal shows that the sample has rather low density of dangling bonds. The photoluminescence intensity of the treated sample de-creases slightly compared to the sample without the treatment and is very stable while storing in at-mosphere. These results show that nitride can be an excellent passivation film on porous silicon and may be important to the practical applications.

The bright and stable porous silicon have been obtained by using damp oxidation at moderate temperature. EPR measurements showed that the density of Si dangling bonds in the sample is lower than that by dry oxidation. We also took FTIR measurements and concluded that the stabilization of the photoluminescence from porous silicon is due to the formation of SiH(O3), SiH(SiO2) and SiH(O2) structure.