中文摘要：

在10Pa的Ar环境气氛下，采用脉冲激光烧蚀方法在玻璃或单晶Si（111）衬底上制备了纳米Si晶薄膜。为了确定能够形成纳米Si晶粒的激光能量密度阈值，在0.40-1.05J／cm^2内实验研究了激光能量密度对纳米Si晶粒形成的影响。扫描电子显微镜（SEM）测量证实，随着激光能量密度的减小，所形成的纳米Si晶粒数目逐渐减少。当激光能量密度低于0.43J／cm^2时，衬底表面不再有纳米Si晶粒形成。从激光烧蚀动力学角度出发，对实验结果进行了定性分析。

英文摘要：

At the ambient pressure of 10 Pa of Ar gas, nanocrystalline silicon （nc-Si） films are deposi- ted on glass or single crystalline（111） Si substrates by pulsed laser ablation. In order to measure the laser energy threshold of the formation of Si nanoparticles, the influence of laser energy density on Si nanoparticles is studied at the laser energy density from 0.40 J/cm^2 to 1.05J/cm^2. Scanning electron microscopy images show that the number of Si nanoparticles decrease with the decrease of laser energy density. Si nanoparticles are not obtained on the substrate when the laser energy density is less than 0.43J/cm^2. The ex- perimental result is analyzed qualitatively on the basis of thermodynamics of laser ablation.