Faculty of Physics, University of Warsaw, Pasteura 7, Warsaw 02-093, Poland.
Nanoscale Res Lett. 2014 Mar 31;9(1):153. doi: 10.1186/1556-276X-9-153.
Reduction of surface plasmon-polariton losses due to their scattering on metal surface roughness still remains a challenge in the fabrication of plasmonic devices for nanooptics. To achieve smooth silver films, we study the dependence of surface roughness on the evaporation temperature in a physical vapor deposition process. At the deposition temperature range 90 to 500 K, the mismatch of thermal expansion coefficients of Ag, Ge wetting layer, and sapphire substrate does not deteriorate the metal surface. To avoid ice crystal formation on substrates, the working temperature of the whole physical vapor deposition process should exceed that of the sublimation at the evaporation pressure range. At optimum room temperature, the root-mean-square (RMS) surface roughness was successfully reduced to 0.2 nm for a 10-nm Ag layer on sapphire substrate with a 1-nm germanium wetting interlayer. Silver layers of 10- and 30-nm thickness were examined using an atomic force microscope (AFM), X-ray reflectometry (XRR), and two-dimensional X-ray diffraction (XRD2).
63.22.Np Layered systems; 68. Surfaces and interfaces; thin films and nanosystems (structure and nonelectronic properties); 81.07.-b Nanoscale materials and structures: fabrication and characterization.
在制造用于纳米光学的等离子体器件时，由于表面等离子体激元的散射，其表面等离子体激元损耗的减少仍然是一个挑战。为了获得光滑的银膜，我们研究了在物理气相沉积过程中蒸发温度对表面粗糙度的依赖关系。在沉积温度范围为 90 至 500 K 时，Ag、Ge 浸润层和蓝宝石衬底的热膨胀系数不匹配不会恶化金属表面。为了避免基板上冰晶的形成，整个物理气相沉积过程的工作温度应高于蒸发压力范围内的升华温度。在最佳室温下，成功地将蓝宝石衬底上的 10nm 厚银层的均方根（RMS）表面粗糙度降低到 0.2nm，同时具有 1nm 的锗润湿层。使用原子力显微镜（AFM）、X 射线反射率（XRR）和二维 X 射线衍射（XRD2）对 10nm 和 30nm 厚的银层进行了研究。
分层系统；68. 表面和界面；薄膜和纳米系统（结构和非电子特性）；81.07.-b 纳米尺度材料和结构：制造和表征。
