Ultralow Reflection from a-Si Nanograss/Si Nanofrustum Double Layers

Authors

  • Srikanth Ravipati,

    1. Institute of Nanotechnology, Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC
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  • Jiann Shieh,

    Corresponding author
    1. Department of Materials Science and Engineering, National United University, Miaoli 36003, Taiwan, ROC
    • Department of Materials Science and Engineering, National United University, Miaoli 36003, Taiwan, ROC.
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  • Fu-Hsiang Ko,

    Corresponding author
    1. Institute of Nanotechnology, Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC
    • Institute of Nanotechnology, Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC
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  • Chen-Chieh Yu,

    1. Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC
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  • Hsuen-Li Chen

    1. Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC
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Abstract

original image

A double-layer nanostructure comprising amorphous Si nanograss on top of Si nanofrustums (NFs) with a total height of 680 nm exhibits ultralow reflection. Almost near-unity absorption and near-zero reflectance result in this layered nanostructure, over a broad range of wavelengths and a wide range of angles of incidence, due to the low packing density of a-Si and the smooth transition of the refractive index from the air to the Si substrate across both the nanograss and NF layers.

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