Nanophotonics in absorbing III-V nanowire arrays
(2013)- Abstract
- We have studied the interaction of light with an array of vertically oriented III-V
semiconductor nanowires both theoretically and experimentally. For the theoretical
studies, electromagnetic modeling has been employed. This modeling shows that with
proper tuning of the nanowire diameter, the absorption per volume semiconductor
material can be 20 times higher in the nanowires than in a corresponding bulk
semiconductor sample. This enhancement occurs when nanophotonic resonances show
up in the nanowires. We have shown that the optical response of a nanowire array can
be described by electrostatics for small-diameter nanowires and by geometrical optics
for large-diameter... (More) - We have studied the interaction of light with an array of vertically oriented III-V
semiconductor nanowires both theoretically and experimentally. For the theoretical
studies, electromagnetic modeling has been employed. This modeling shows that with
proper tuning of the nanowire diameter, the absorption per volume semiconductor
material can be 20 times higher in the nanowires than in a corresponding bulk
semiconductor sample. This enhancement occurs when nanophotonic resonances show
up in the nanowires. We have shown that the optical response of a nanowire array can
be described by electrostatics for small-diameter nanowires and by geometrical optics
for large-diameter nanowires. None of these two limit cases showed resonances,
motivating the interest for the intermediate nanophotonic regime where the diameter
of the nanowires is comparable to the wavelength of the incident light.
Supported by theoretical analysis, we have shown experimentally a resonant
photodetection response in an InAsSb nanowire array in the infrared region, which is
of potential interest for thermal imaging and chemical analysis. Furthermore, we have
demonstrated a solar cell based on InP nanowires. The nanowire-array solar cell
showed an efficiency of 13.8 % and converted more than 70 % of the above-bandgap
photons into electron-hole pairs that contributed to the short-circuit current, even
though the nanowires covered only 12 % of the surface.
By combining the electromagnetic modeling with reflectance measurements, we have
developed an optical method for simultaneously measuring both the diameter and the
length of nanowires in large-area arrays. The accuracy of the method is comparable to
that of scanning electron microscopy. Furthermore, we have developed tools for
studying the crystal-phase dependent optical response of III-V materials. The studies
showed that a tuning of the crystal phase, which is possible in the nanowire geometry,
can be used for enabling and disabling strongly absorbing nanophotonic resonances in
nanowire arrays. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3768636
- author
- Anttu, Nicklas LU
- supervisor
- opponent
-
- Professor Yablonovitch, Eli, University of California, Berkeley, USA
- organization
- publishing date
- 2013
- type
- Thesis
- publication status
- published
- subject
- keywords
- III-V semiconductor materials, Nanophotonics, nanowires, electromagnetic modeling, Fysicumarkivet A:2013:Anttu
- pages
- 200 pages
- defense location
- Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Lund University Faculty of Engineering
- defense date
- 2013-06-14 14:00:00
- ISBN
- 978-91-7473-550-5
- language
- English
- LU publication?
- yes
- id
- 26c12e93-f2a9-484c-897b-1c524b0e87fe (old id 3768636)
- date added to LUP
- 2016-04-04 13:33:56
- date last changed
- 2018-11-22 17:20:49
@phdthesis{26c12e93-f2a9-484c-897b-1c524b0e87fe,
abstract = {{We have studied the interaction of light with an array of vertically oriented III-V<br/><br>
semiconductor nanowires both theoretically and experimentally. For the theoretical<br/><br>
studies, electromagnetic modeling has been employed. This modeling shows that with<br/><br>
proper tuning of the nanowire diameter, the absorption per volume semiconductor<br/><br>
material can be 20 times higher in the nanowires than in a corresponding bulk<br/><br>
semiconductor sample. This enhancement occurs when nanophotonic resonances show<br/><br>
up in the nanowires. We have shown that the optical response of a nanowire array can<br/><br>
be described by electrostatics for small-diameter nanowires and by geometrical optics<br/><br>
for large-diameter nanowires. None of these two limit cases showed resonances,<br/><br>
motivating the interest for the intermediate nanophotonic regime where the diameter<br/><br>
of the nanowires is comparable to the wavelength of the incident light.<br/><br>
<br/><br>
Supported by theoretical analysis, we have shown experimentally a resonant<br/><br>
photodetection response in an InAsSb nanowire array in the infrared region, which is<br/><br>
of potential interest for thermal imaging and chemical analysis. Furthermore, we have<br/><br>
demonstrated a solar cell based on InP nanowires. The nanowire-array solar cell<br/><br>
showed an efficiency of 13.8 % and converted more than 70 % of the above-bandgap<br/><br>
photons into electron-hole pairs that contributed to the short-circuit current, even<br/><br>
though the nanowires covered only 12 % of the surface.<br/><br>
<br/><br>
By combining the electromagnetic modeling with reflectance measurements, we have<br/><br>
developed an optical method for simultaneously measuring both the diameter and the<br/><br>
length of nanowires in large-area arrays. The accuracy of the method is comparable to<br/><br>
that of scanning electron microscopy. Furthermore, we have developed tools for<br/><br>
studying the crystal-phase dependent optical response of III-V materials. The studies<br/><br>
showed that a tuning of the crystal phase, which is possible in the nanowire geometry,<br/><br>
can be used for enabling and disabling strongly absorbing nanophotonic resonances in<br/><br>
nanowire arrays.}},
author = {{Anttu, Nicklas}},
isbn = {{978-91-7473-550-5}},
keywords = {{III-V semiconductor materials; Nanophotonics; nanowires; electromagnetic modeling; Fysicumarkivet A:2013:Anttu}},
language = {{eng}},
school = {{Lund University}},
title = {{Nanophotonics in absorbing III-V nanowire arrays}},
url = {{https://lup.lub.lu.se/search/files/6151427/3768637.pdf}},
year = {{2013}},
}