脉冲激光烧蚀制备纳米Si晶粒成核区位置的确定

为了确定纳米Si晶粒气相成核的位置，采用XeCl准分子激光器，在10Pa氩气环境下，烧蚀高阻抗单晶Si靶，在距离等离子羽正下方2.0cm处、与其轴线平行放置一系列单晶Si或玻璃衬底，沉积制备了纳米Si薄膜. X射线衍射、Raman散射、扫描电子显微镜和原子力显微镜结果均显示，纳米Si晶粒只在距靶约0.5—2.8cm平行距离范围内的样品上形成，在此范围内，随着离靶平行距离的增大，所形成的纳米Si晶粒的平均尺寸逐渐减小，并且晶粒尺寸的分布也发生变化. 根据成核区起始和终止的突变特征，结合晶粒形成后的平抛运动规律，对晶粒气相成核的位置进行了估算. 关键词： 纳米Si晶粒 脉冲激光烧蚀 成核区

Determination of the region where Si nanoparticles form during pulsed laser ablation

To determinate the nucleation region of Si nanoparticles formed in gas phase, the single crystalline Si target with high resistivity was ablated by a XeCl excimer laser in pure Ar gas under the ambient pressure of 10Pa, and the nanocrystalline Si films were systemically deposited on pieces of glass or single crystalline (111) Si substrates lined up at a distance of 2.0cm under the plasma. The Raman and X-ray diffraction spectra, scanning electron microscope and atomic force microscope images of the films show that Si nanoparticles were formed on the pieces placed at horizontal distances 0.5 to 2.8cm from the target, the average size of Si nanoparticles monotonically decreased with the distance increasing. The region that Si nanoparticles form in gas phase was estimated on the basis of the PLA dynamics.