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在室温、10 Pa氩气环境下,采用脉冲激光烧蚀(PLA)技术,通过改变激光能量密度,在烧蚀点正下方、与烧蚀羽辉轴线平行放置的衬底上沉积制备了一系列纳米Si晶薄膜。采用SEM、Raman散射谱和XRD对纳米Si晶薄膜进行了表征。结果表明:沉积在衬底上的纳米Si晶粒分布在距靶一定的范围内,晶粒尺寸随与靶面距离的增加先增大后减小;随着激光能量密度的增加,晶粒在衬底上的沉积范围双向展宽,但沉积所得最大晶粒尺寸基本保持不变,只是沉积位置随激光能量密度的增加相应后移。结合流体力学模型、成核分区模型和热动力学方程,通过模拟激光烧蚀靶材的动力学过程,对纳米Si晶粒的成核生长动力学过程进行了研究。
A series of depositions were made at room temperature using a pulsed laser ablation (PLA) technique at room temperature under argon at 10 Pa by depositing a laser energy density directly beneath the ablation point and parallel to the ablation plume axis Nanocrystalline Si film. Nanostructured Si films were characterized by SEM, Raman scattering and XRD. The results show that the nano-Si grains deposited on the substrate distribute within a certain range from the target, and the grain size first increases and then decreases with the increase of the distance from the target surface. With the increase of laser energy density, The deposition range on the substrate is broadened bidirectionally, but the maximum grain size obtained by deposition is basically unchanged, but the deposition position is correspondingly shifted with the increase of laser energy density. Combining the hydrodynamics model, nucleation zoning model and thermodynamic equation, the nucleation and growth kinetics of nano-Si grains were studied by simulating the laser ablation target kinetics.