Abstract We study photoluminescence (PL) and time-resolve PL to investigate the luminescence mechanism properties of the silicon quantum dots grown in silicon nitride layers. The silicon quantum dots were fabricated by atmospheric pressure chemical vapor deposition (APCVD) method. Because of the increase of the oxygen-related defect (self-trapping holes), the PL intensity decreases with time-dependent in the air. From the analysis of the energy dependent carrier lifetime, we observed the carrier localization of the silicon quantum dots. In the temperature dependence of PL studies, the activation energy due to thermal activation is estimated to be 46 meV, in agreement with the depth of carrier localization energy. From the analysis of the temperature-dependence radiative lifetime, we observed the carrier lifetime is independent of temperature.