Abstract: Rare earths (La, Nd) have been implanted into the Si substrate and thermal SiO₂ samples. The Rutherford Backscattering Spectrum (RBS) at room temperature for the samples annealed under O₂ at different temperature was measured. The photoluminescence measurements show that all the samples possess stable blue-violet photoluminescence properties under the ultra-violet light excitation (λ_ex = 250nm). Thephotoluminescence efficiency for the samples varies with the anneal condition, and the light emission is more intense when the impurity doped concentration is greater within a certain limits. The photoluminescence mechanism for our sample is also discussed.