Frederiksen Rune, Tutuncuoglu Gozde, Matteini Federico, Martinez Karen L, Fontcuberta I Morral Anna, Alarcon-Llado Esther
Bio-Nanotechnology and Nanomedicine Laboratory, Department of Chemistry & Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
Laboratory of Semiconductor Materials, Institute of Materials, School of Engineering, EPFL, 1015 Lausanne, Switzerland.
ACS Photonics. 2017 Sep 20;4(9):2235-2241. doi: 10.1021/acsphotonics.7b00434. Epub 2017 Aug 21.
Semiconductor nanowires are promising building blocks for next-generation photonics. Indirect proofs of large absorption cross sections have been reported in nanostructures with subwavelength diameters, an effect that is even more prominent in vertically standing nanowires. In this work we provide a three-dimensional map of the light around vertical GaAs nanowires standing on a substrate by using fluorescence confocal microscopy, where the strong long-range disruption of the light path along the nanowire is illustrated. We find that the actual long-distance perturbation is much larger in size than calculated extinction cross sections. While the size of the perturbation remains similar, the intensity of the interaction changes dramatically over the visible spectrum. Numerical simulations allow us to distinguish the effects of scattering and absorption in the nanowire leading to these phenomena. This work provides a visual understanding of light absorption in semiconductor nanowire structures, which is of high interest for solar energy conversion applications.
半导体纳米线是下一代光子学中很有前景的构建模块。在具有亚波长直径的纳米结构中已报道了大吸收截面的间接证据，这种效应在垂直站立的纳米线中更为显著。在这项工作中，我们通过使用荧光共聚焦显微镜提供了位于衬底上的垂直砷化镓纳米线周围光的三维图谱，其中展示了沿纳米线的光路的强烈长程干扰。我们发现实际的长距离扰动在尺寸上比计算出的消光截面大得多。虽然扰动的尺寸保持相似，但相互作用的强度在可见光谱范围内变化很大。数值模拟使我们能够区分纳米线中导致这些现象的散射和吸收效应。这项工作提供了对半导体纳米线结构中光吸收的直观理解，这对于太阳能转换应用具有高度的重要性。
