Abstract Photoluminescence(PL) of silicon nanocrystals were studied using the continuous and time-resolved PL measurements.The silicon nanocrystals were fabricated by atmospheric pressure chemical vapor deposition (APCVD) method. When the silicon nanocrystals surface was passivated with oxygen atoms,the intensity of red luminescence increased more than one order of magnitude. Furthermore,the temperature dependent PL intensity shows that,the recombination process includes radiative and nonradiative recombination process. The localization effect also proved by emission dependent time-resolved PL.