Si基片上Ag膜的微结构及光学常数研究

用真空蒸镀法在室温Si基片上制备了Ag薄膜 ,并用X射线衍射及反射式椭偏光谱技术对薄膜的微结构和光学常数进行了测试分析。结构分析表明 :制备的Ag膜晶体仍为面心立方结构 ,呈多晶状态 ,晶粒择优取向于 [111],平均晶粒尺寸约为 2 2 7nm ,晶格常数 ( 0 4 0 860nm)比标准值 ( 0 4 0 862nm)略小。在 2 5 0～ 83 0nm波长范围椭偏光谱测量结果表明 :Ag膜的折射率和消光系数分别在 0 15～ 1 4 9和 0 3 1～ 5 77之间。与块材相比 ,在块材的折射率大于一定值 ( 1 0 0～ 1 3 3 )时 ,Ag膜的折射率比块材的小 ,其余范围则增大 ;Ag膜的消光系数减小。并给出了一套较为可靠的、具有实用价值的Ag薄膜光学常数。

Microstructures and Optical Properties of Vacuum Deposited Ag Films

Ag films,grown on Si substrates by vacuum deposition,were studied with X ray diffraction and reflecting ellipsometry.The results show that the polycrystalline Ag films consist of fcc Ag nanoparticles with an average size of 22.7 nm and a preferential growth direction of .The lattice constant of the Ag nanoparticle (0.40860 nm) was found to be slightly smaller than that of the powder (0.40862 nm).The optical constants of the film in the range of 250 to 830 nm,which were found to differ from those of the bulk Ag,were evaluated.