采用XeCl准分子脉冲激光,在室温、真空环境下烧蚀银靶,通过改变激光能量密度和靶衬间距,在与靶面平行放置的Si(111)衬底上沉积了一系列纳米银晶薄膜。利用扫描电镜以及X射线衍射仪、选区电子衍射技术对薄膜进行表征,结果表明:薄膜由不同尺寸的银纳米晶粒组成;在固定激光能量密度的条件下,随着靶衬间距增加,薄膜的厚度和晶粒尺寸逐渐减小,晶粒间的聚合程度减弱,薄膜(111)晶面的XRD特征谱线强度减弱,(200)晶面的特征谱线强度增强;在固定靶衬间距的条件下,随着激光能量密度的增大,薄膜的厚度和晶粒尺寸逐渐增大,晶粒间的聚合程度增强,薄膜(111)晶面的特征谱线强度增强,(200)晶面的特征谱线强度略有减弱。结合晶粒成核和传输特性、烧蚀粒子迁移率,以及薄膜沿不同晶面生长所需表面能存在差异的情况,对实验结果进行了分析。

A silver (Ag) target was ablated using the XeCl excimer laser at room temperature in vacuum. Films were deposited on the Si(111) substrates parallel to the target surface. The scanning electron microscopy, X-ray diffraction (XRD), and selected area electron diffraction analysis results denote that the deposited films comprise Ag nanoparticles with different sizes. The fixed laser fluence increases the distance from the target to the substrate, decreases the nanoparticle size and depth of the film, and weakens the combinative extent of the nanoparticles. Further, the XRD spectrum intensity of the crystallographic face of (111) decreases, whereas that of the crystallographic face of (200) increases. When the distance from the target to the substrate is fixed, the nanoparticle size and depth of the film increases with the increasing laser fluence, and the combinative extent of the nanoparticles increases. The XRD spectrum intensity of the crystallographic face of (111) increases, whereas that of the crystallographic face of (200) barely decreases. Furthermore, the experimental results are analyzed on the basis of the nucleation and transition of the nanoparticles, mobility of the ablated particles, and surface energy required in film growth along different crystallographic faces.