Different from bulk silicon crystal, nano-sized Si crystalline embedded in dielectric medium is known as an efficient light emitting center. In nano-crystalline Si, excitonic electron-hole pairs are considered to be attributed to radiative recombination. But the defects surrounding crystalline nc-Si suppress light emitting, which works as a non-radiative decay path. Hydrogen is usually utilized in order to encapsulate the dangling bonds in the Si:SiO2 interface, dramatically enhancing luminescence yield from nc-Si embedded in dielectric medium. Unfortunately because hydrogen has higher mobility in the matrix, subsequent thermal processes may reduce the enhancement effect. Thus instead of easily reversible hydrogen, phosphorus was introduced by implantation, and was to have the same effect and to be resistive to thermal treatments. Samples were prepared by 400 keV Si implantation with dose of 1 × 1017 Si /cm2 and by multi-energy P implantation to make relatively uniform P concentration in the region where implanted Si ions are distributed. Precipitation of crystalline silicon was obtained by annealing at 1100°C for 2 hour in pure Ar environment. Experimental data such as enhancement effect of PL yield, decay time, peak shift for the phosphorus implanted nano-crystalline Si are shown, and the possible mechanisms are discussed.