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Enhanced broadband absorption in nanowire arrays with integrated Bragg reflectors

Aghaeipour, Mahtab LU and Pettersson, Håkan LU (2018) In Nanophotonics 7(5). p.819-825
Abstract

A near-unity unselective absorption spectrum is desirable for high-performance photovoltaics. Nanowire (NW) arrays are promising candidates for efficient solar cells due to nanophotonic absorption resonances in the solar spectrum. The absorption spectra, however, display undesired dips between the resonance peaks. To achieve improved unselective broadband absorption, we propose to enclose distributed Bragg reflectors (DBRs) in the bottom and top parts of indium phosphide (InP) NWs, respectively. We theoretically show that by enclosing only two periods of In0.56Ga0.44As/InP DBRs, an unselective 78% absorption efficiency (72% for NWs without DBRs) is obtained at normal incidence in the spectral range from 300 nm to... (More)

A near-unity unselective absorption spectrum is desirable for high-performance photovoltaics. Nanowire (NW) arrays are promising candidates for efficient solar cells due to nanophotonic absorption resonances in the solar spectrum. The absorption spectra, however, display undesired dips between the resonance peaks. To achieve improved unselective broadband absorption, we propose to enclose distributed Bragg reflectors (DBRs) in the bottom and top parts of indium phosphide (InP) NWs, respectively. We theoretically show that by enclosing only two periods of In0.56Ga0.44As/InP DBRs, an unselective 78% absorption efficiency (72% for NWs without DBRs) is obtained at normal incidence in the spectral range from 300 nm to 920 nm. Under oblique light incidence, the absorption efficiency is enhanced up to about 85% at an incidence angle of 50°. By increasing the number of DBR periods from two to five, the absorption efficiency is further enhanced up to 95% at normal incidence. In this work, we calculated optical spectra for InP NWs, but the results are expected to be valid for other direct band gap III-V semiconductor materials. We believe that our proposed idea of integrating DBRs in NWs offers great potential for high-performance photovoltaic applications.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
distributed Bragg reflectors (DBRs), light trapping, nanowires, photovoltaics
in
Nanophotonics
volume
7
issue
5
pages
819 - 825
publisher
De Gruyter
external identifiers
  • scopus:85045636459
ISSN
2192-8614
DOI
10.1515/nanoph-2017-0101
language
English
LU publication?
yes
id
39940152-4a1c-4597-9802-0b911025da8e
date added to LUP
2018-05-07 13:37:51
date last changed
2019-02-20 11:16:27
@article{39940152-4a1c-4597-9802-0b911025da8e,
  abstract     = {<p>A near-unity unselective absorption spectrum is desirable for high-performance photovoltaics. Nanowire (NW) arrays are promising candidates for efficient solar cells due to nanophotonic absorption resonances in the solar spectrum. The absorption spectra, however, display undesired dips between the resonance peaks. To achieve improved unselective broadband absorption, we propose to enclose distributed Bragg reflectors (DBRs) in the bottom and top parts of indium phosphide (InP) NWs, respectively. We theoretically show that by enclosing only two periods of In<sub>0.56</sub>Ga<sub>0.44</sub>As/InP DBRs, an unselective 78% absorption efficiency (72% for NWs without DBRs) is obtained at normal incidence in the spectral range from 300 nm to 920 nm. Under oblique light incidence, the absorption efficiency is enhanced up to about 85% at an incidence angle of 50°. By increasing the number of DBR periods from two to five, the absorption efficiency is further enhanced up to 95% at normal incidence. In this work, we calculated optical spectra for InP NWs, but the results are expected to be valid for other direct band gap III-V semiconductor materials. We believe that our proposed idea of integrating DBRs in NWs offers great potential for high-performance photovoltaic applications.</p>},
  author       = {Aghaeipour, Mahtab and Pettersson, Håkan},
  issn         = {2192-8614},
  keyword      = {distributed Bragg reflectors (DBRs),light trapping,nanowires,photovoltaics},
  language     = {eng},
  month        = {05},
  number       = {5},
  pages        = {819--825},
  publisher    = {De Gruyter},
  series       = {Nanophotonics},
  title        = {Enhanced broadband absorption in nanowire arrays with integrated Bragg reflectors},
  url          = {http://dx.doi.org/10.1515/nanoph-2017-0101},
  volume       = {7},
  year         = {2018},
}