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为研究纳米硅晶粒成核生长动力学过程,采用脉冲激光烧蚀(PLA)技术,在室温,50～200 Pa的氩气氛围中,通过引入垂直于烧蚀羽辉轴线的外加气流,在水平放置的衬底上沉积了一系列纳米Si晶薄膜。扫描电子显微镜(SEM)、拉曼(Raman)散射和X射线衍射(XRD)检测结果表明,未引入气流时,衬底上相同位置处晶粒尺寸随气体压强的增大逐渐减小;在距靶1～2 cm范围内引入气流后,尺寸变化规律与未引入气流时相反。通过分析晶粒尺寸及其在衬底上的位置分布特点,结合流体力学模型和热动力学方程,分析得出在激光能量密度一定的条件下,环境气体压强、烧蚀粒子温度和密度共同影响着纳米晶粒的成核生长。
In order to study the nucleation and growth kinetics of nanosized silicon grains, pulsed laser ablation (PLA) was used to investigate the nucleation and growth kinetics of nanosized silicon grains by introducing pulsed laser ablation A series of nano-Si thin films have been deposited on the horizontally placed substrate. Scanning electron microscopy (SEM), Raman scattering and X-ray diffraction (XRD) results show that the grain size at the same position on the substrate decreases with the increase of gas pressure without introducing air flow. After the target air flow was introduced in the range of 1 ~ 2 cm, the dimensional change was opposite to that when no air flow was introduced. By analyzing the grain size and its distribution on the substrate, combined with the hydrodynamic model and the thermodynamic equation, it is concluded that under the certain laser energy density, the influence of the ambient gas pressure, the temperature and density of the ablation particles The nucleation and growth of nanocrystalline grains.