Goetz Selina, Bauch Martin, Dimopoulos Theodoros, Trassl Stephan
AIT Austrian Institute of Technology, Center for Energy, Photovoltaic Systems Giefinggasse 4 1210 Vienna Austria
HUECK FOLIEN GmbH Gewerbepark 30 4342 Baumgartenberg Austria.
Nanoscale Adv. 2020 Jan 23;2(2):869-877. doi: 10.1039/c9na00762h. eCollection 2020 Feb 18.
In this study, ultrathin silver plasmonic nanostructures are fabricated by sputter deposition on substrates patterned by nanoimprint lithography, without additional lift-off processes. Detailed investigation of silver growth on different substrates results in a structured, defect-free silver film with thickness down to 6 nm, deposited on a thin layer of doped zinc oxide. Variation of the aspect ratio of the nanostructure reduces grain formation at the flanks, allowing for well-separated disk and hole arrays, even though conventional magnetron sputtering is less directional than evaporation. The resulting disk-hole array features high average transmittance in the visible range of 71% and a strong plasmonic dipole resonance in the near-infrared region. It is shown that the ultrathin Ag film exhibits even lower optical losses in the NIR range compared to known bulk optical properties. The presented FDTD simulations agree well with experimental spectra and show that for defect-free, ultrathin Ag nanostructures, bulk optical properties of Ag are sufficient for a reliable simulation-based design.
在本研究中，通过溅射沉积在由纳米压印光刻图案化的基板上制备超薄银等离子体纳米结构，无需额外的剥离工艺。对银在不同基板上生长的详细研究得到了一种结构良好、无缺陷的银膜，其厚度低至6nm，沉积在掺杂氧化锌的薄层上。纳米结构纵横比的变化减少了侧面的晶粒形成，即使传统磁控溅射的方向性比蒸发小，也能形成分离良好的圆盘和孔阵列。所得的盘-孔阵列在可见光范围内具有71%的高平均透过率，在近红外区域具有强烈的等离子体偶极共振。结果表明，与已知的块状光学性质相比，超薄银膜在近红外范围内表现出更低的光学损耗。所呈现的有限时域差分（FDTD）模拟与实验光谱吻合良好，表明对于无缺陷的超薄银纳米结构，银的块状光学性质足以用于基于模拟的可靠设计。
