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Drastically increased absorption in vertical semiconductor nanowire arrays: A non-absorbing dielectric shell makes the difference

Anttu, Nicklas LU ; Namazi, Kousar; Wu, Phillip LU ; Yang, Pengfei; Xu, Hongxing LU ; Xu, Hongqi LU and Håkanson, Ulf LU (2012) In Nano Reseach 5(12). p.863-874
Abstract
Enhanced absorption of especially long wavelength light is needed to enable the full potential of semiconductor nanowire (NW) arrays for optoelectronic applications. We show both experimentally and theoretically that a transparent dielectric shell (Al2O3 coating) can drastically improve the absorption of light in InAs NW arrays. With an appropriate thickness of the Al2O3 shell, we achieve four times stronger absorption in the NWs compared to uncoated NWs and twice as good absorption as when the dielectric completely fills the space between the NWs. We provide detailed theoretical analysis from a combination of full electrodynamic modeling and intuitive electrostatic approximations. This reveals how the incident light penetrates better into... (More)
Enhanced absorption of especially long wavelength light is needed to enable the full potential of semiconductor nanowire (NW) arrays for optoelectronic applications. We show both experimentally and theoretically that a transparent dielectric shell (Al2O3 coating) can drastically improve the absorption of light in InAs NW arrays. With an appropriate thickness of the Al2O3 shell, we achieve four times stronger absorption in the NWs compared to uncoated NWs and twice as good absorption as when the dielectric completely fills the space between the NWs. We provide detailed theoretical analysis from a combination of full electrodynamic modeling and intuitive electrostatic approximations. This reveals how the incident light penetrates better into the absorbing NW core with increasing thickness of the dielectric shell until a resonant shell thickness is reached. We provide a simple description of how to reach this strongly absorbing resonance condition, making our results easy to apply for a broad wavelength range and a multifold of semiconductor and dielectric coating material combinations. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Nanowire array, InAs, absorption, photovoltaics, core-shell, Al2O3, coating
in
Nano Reseach
volume
5
issue
12
pages
863 - 874
publisher
Springer
external identifiers
  • wos:000312406700004
  • scopus:84871263229
ISSN
1998-0124
DOI
10.1007/s12274-012-0270-x
language
English
LU publication?
yes
id
3880b846-6c21-4c12-946f-1c2bf3e33b13 (old id 3368021)
date added to LUP
2013-02-01 09:53:46
date last changed
2017-04-30 04:23:14
@article{3880b846-6c21-4c12-946f-1c2bf3e33b13,
  abstract     = {Enhanced absorption of especially long wavelength light is needed to enable the full potential of semiconductor nanowire (NW) arrays for optoelectronic applications. We show both experimentally and theoretically that a transparent dielectric shell (Al2O3 coating) can drastically improve the absorption of light in InAs NW arrays. With an appropriate thickness of the Al2O3 shell, we achieve four times stronger absorption in the NWs compared to uncoated NWs and twice as good absorption as when the dielectric completely fills the space between the NWs. We provide detailed theoretical analysis from a combination of full electrodynamic modeling and intuitive electrostatic approximations. This reveals how the incident light penetrates better into the absorbing NW core with increasing thickness of the dielectric shell until a resonant shell thickness is reached. We provide a simple description of how to reach this strongly absorbing resonance condition, making our results easy to apply for a broad wavelength range and a multifold of semiconductor and dielectric coating material combinations.},
  author       = {Anttu, Nicklas and Namazi, Kousar and Wu, Phillip and Yang, Pengfei and Xu, Hongxing and Xu, Hongqi and Håkanson, Ulf},
  issn         = {1998-0124},
  keyword      = {Nanowire array,InAs,absorption,photovoltaics,core-shell,Al2O3,coating},
  language     = {eng},
  number       = {12},
  pages        = {863--874},
  publisher    = {Springer},
  series       = {Nano Reseach},
  title        = {Drastically increased absorption in vertical semiconductor nanowire arrays: A non-absorbing dielectric shell makes the difference},
  url          = {http://dx.doi.org/10.1007/s12274-012-0270-x},
  volume       = {5},
  year         = {2012},
}