电场中不同能量密度激光烧蚀制备纳米硅晶粒分布特性

摘要

在室温和10 Pa氩气环境中,引入平行于靶面方向的直流电场,通过改变脉冲激光能量密度烧蚀单晶硅靶,在与羽辉轴线呈不同角度的衬底上沉积纳米硅晶薄膜.利用扫描电子显微镜和拉曼散射谱对沉积样品进行分析,结果表明:随着激光能量密度的增加,位于相同角度衬底上的晶粒尺寸和面密度逐渐变大；在同一激光能量密度下,零度角处衬底上的晶粒尺寸和面密度最大,且靠近接地极板处的值比与之对称角度处略大.通过朗缪尔探针对不同能量密度下烧蚀羽辉中硅离子密度变化的诊断、结合成核区内晶粒成核生长动力学过程,对晶粒分布特性进行了分析.%With changing laser fluence,Si nano-crystal films were prepared by the pulsed laser ablation in direct current electric field that paralleled to target surface in Ar gas of 10 Pa at room temperature.The substrates were fixed on the position with different angles to plume axis.The morphology and composition of samples were characterized by scanning electron microscopy and Raman scattering spectrums.The results indicate that the average size and the area density of nanoparticles increase with the addition of laser fluence at the same angle.The average size and the area density of nanoparticles at direction of plume axis are the biggest when the laser fluence keeps invariable,furthermore,the values of them near grounded board are bigger than those near the positive board symmetrical.The results were analyzed on the base of diagnosis of changes of silicon ions density through Langmuir probe and dynamics of nucleation and growth process of nanoparticles in the nucleation region.