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Increased absorption in InAsSb nanowire clusters through coupled optical modes

Svensson, Johannes LU ; Chen, Yang LU ; Anttu, Nicklas LU ; Pistol, Mats Erik LU and Wernersson, Lars Erik LU (2017) In Applied Physics Letters 110(8).
Abstract

Nanowires can act as efficient light absorbers where waveguide modes are resonant to specific wavelengths. This resonant wavelength can easily be tuned by the nanowire dimensions, but the absorption of infrared radiation requires diameters of hundreds of nm, which is difficult to achieve using epitaxial growth. Here, we demonstrate that infrared absorption in InAsSb nanowires with the diameters of only 140 nm grown on Si substrates can be enhanced resonantly by placing them closely packed in clusters of different sizes. We find that coating the nanowires with a dielectric to optically connect them results in an efficient absorption diameter far exceeding the diameter of the constituent nanowires and that the cut-off wavelength is... (More)

Nanowires can act as efficient light absorbers where waveguide modes are resonant to specific wavelengths. This resonant wavelength can easily be tuned by the nanowire dimensions, but the absorption of infrared radiation requires diameters of hundreds of nm, which is difficult to achieve using epitaxial growth. Here, we demonstrate that infrared absorption in InAsSb nanowires with the diameters of only 140 nm grown on Si substrates can be enhanced resonantly by placing them closely packed in clusters of different sizes. We find that coating the nanowires with a dielectric to optically connect them results in an efficient absorption diameter far exceeding the diameter of the constituent nanowires and that the cut-off wavelength is redshifted with an increasing cluster diameter. Numerical simulations are in agreement with the experimental results and demonstrate that if nanowires are positioned in clusters, a peak absorptance of 20% is possible at 5.6 μm with only 3% surface coverage. This absorptance is 200 times higher than for wires placed in an equidistant pattern. Our findings have direct implications for the design of efficient nanowire based photodetectors and solar cells.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Physics Letters
volume
110
issue
8
publisher
American Institute of Physics
external identifiers
  • scopus:85013863802
  • wos:000394762600004
ISSN
0003-6951
DOI
10.1063/1.4977032
language
English
LU publication?
yes
id
62ce050d-1a78-4d25-bc75-673008ae87c8
date added to LUP
2017-03-08 10:58:40
date last changed
2018-01-07 11:54:31
@article{62ce050d-1a78-4d25-bc75-673008ae87c8,
  abstract     = {<p>Nanowires can act as efficient light absorbers where waveguide modes are resonant to specific wavelengths. This resonant wavelength can easily be tuned by the nanowire dimensions, but the absorption of infrared radiation requires diameters of hundreds of nm, which is difficult to achieve using epitaxial growth. Here, we demonstrate that infrared absorption in InAsSb nanowires with the diameters of only 140 nm grown on Si substrates can be enhanced resonantly by placing them closely packed in clusters of different sizes. We find that coating the nanowires with a dielectric to optically connect them results in an efficient absorption diameter far exceeding the diameter of the constituent nanowires and that the cut-off wavelength is redshifted with an increasing cluster diameter. Numerical simulations are in agreement with the experimental results and demonstrate that if nanowires are positioned in clusters, a peak absorptance of 20% is possible at 5.6 μm with only 3% surface coverage. This absorptance is 200 times higher than for wires placed in an equidistant pattern. Our findings have direct implications for the design of efficient nanowire based photodetectors and solar cells.</p>},
  articleno    = {081104},
  author       = {Svensson, Johannes and Chen, Yang and Anttu, Nicklas and Pistol, Mats Erik and Wernersson, Lars Erik},
  issn         = {0003-6951},
  language     = {eng},
  month        = {02},
  number       = {8},
  publisher    = {American Institute of Physics},
  series       = {Applied Physics Letters},
  title        = {Increased absorption in InAsSb nanowire clusters through coupled optical modes},
  url          = {http://dx.doi.org/10.1063/1.4977032},
  volume       = {110},
  year         = {2017},
}