Abstract: Monte Carlo method was used to simulate silicon nanoparticles produced by pulsed laser ablation in this paper .Combined with the drag force model , the degree of supersaturation suitable for the nucleation and growth was calculated .The results show that the substrate of the secondary sputter causing the nucleation times increase , which lead to the number of small size grains increase; the range of the supersaturation degree suitable for nucleation and growth is different , when the degree of supersaturation is larger ( >2600 ) the nucleation times is more and the growth times is less; when the degree of supersaturation is smaller (250-2600) the growth times is more and the nucleation times is less .

Key words: Monte Carlo method was used to simulate silicon nanoparticles produced by pulsed laser ablation in this paper .Combined with the drag force model , the degree of supersaturation suitable for the nucleation and growth was calculated .The results show that the substrate of the secondary sputter causing the nucleation times increase , which lead to the number of small size grains increase; the range of the supersaturation degree suitable for nucleation and growth is different , when the degree of supersaturation is larger ( >2600 ) the nucleation times is more and the growth times is less; when the degree of supersaturation is smaller (250-2600) the growth times is more and the nucleation times is less .