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Time-resolved photoluminescence characterization of GaAs nanowire arrays on native substrate

Dagyte, Vilgaile LU ; Barrigón, Enrique LU ; Zhang, Wei LU ; Zeng, Xulu LU ; Heurlin, Magnus LU ; Otnes, Gaute LU ; Anttu, Nicklas LU and Borgström, Magnus T. LU (2017) In Nanotechnology 28(50).
Abstract

Time-resolved photoluminescence (TRPL) measurements of nanowires (NWs) are often carried out on broken-off NWs in order to avoid the ensemble effects as well as substrate contribution. However, the development of NW-array solar cells could benefit from non-destructive optical characterization to allow faster feedback and further device processing. With this work, we show that different NW array and substrate spectral behaviors with delay time and excitation power can be used to determine which part of the sample dominates the detected spectrum. Here, we evaluate TRPL characterization of dense periodic as-grown GaAs NW arrays on a p-type GaAs substrate, including a sample with uncapped GaAs NWs and several samples passivated with AlGaAs... (More)

Time-resolved photoluminescence (TRPL) measurements of nanowires (NWs) are often carried out on broken-off NWs in order to avoid the ensemble effects as well as substrate contribution. However, the development of NW-array solar cells could benefit from non-destructive optical characterization to allow faster feedback and further device processing. With this work, we show that different NW array and substrate spectral behaviors with delay time and excitation power can be used to determine which part of the sample dominates the detected spectrum. Here, we evaluate TRPL characterization of dense periodic as-grown GaAs NW arrays on a p-type GaAs substrate, including a sample with uncapped GaAs NWs and several samples passivated with AlGaAs radial shell of varied composition and thickness. We observe a strong spectral overlap of substrate and NW signals and find that the NWs can absorb part of the substrate luminescence signal, thus resulting in a modified substrate signal. The level of absorption depends on the NW-array geometry, making a deconvolution of the NW signal very difficult. By studying TRPL of substrate-only and as-grown NWs at 770 and 400 nm excitation wavelengths, we find a difference in spectral behavior with delay time and excitation power that can be used to assess whether the signal is dominated by the NWs. We find that the NW signal dominates with 400 nm excitation wavelength, where we observe two different types of excitation power dependence for the NWs capped with high and low Al composition shells. Finally, from the excitation power dependence of the peak TRPL signal, we extract an estimate of background carrier concentration in the NWs.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
background doping, nanowire arrays, substrate signal, TRPL
in
Nanotechnology
volume
28
issue
50
publisher
IOP Publishing
external identifiers
  • scopus:85035339526
  • wos:000416030600002
ISSN
0957-4484
DOI
10.1088/1361-6528/aa974b
language
English
LU publication?
yes
id
8054da19-f103-4755-b310-21674347ce1a
date added to LUP
2017-12-12 13:15:59
date last changed
2018-01-16 13:27:42
@article{8054da19-f103-4755-b310-21674347ce1a,
  abstract     = {<p>Time-resolved photoluminescence (TRPL) measurements of nanowires (NWs) are often carried out on broken-off NWs in order to avoid the ensemble effects as well as substrate contribution. However, the development of NW-array solar cells could benefit from non-destructive optical characterization to allow faster feedback and further device processing. With this work, we show that different NW array and substrate spectral behaviors with delay time and excitation power can be used to determine which part of the sample dominates the detected spectrum. Here, we evaluate TRPL characterization of dense periodic as-grown GaAs NW arrays on a p-type GaAs substrate, including a sample with uncapped GaAs NWs and several samples passivated with AlGaAs radial shell of varied composition and thickness. We observe a strong spectral overlap of substrate and NW signals and find that the NWs can absorb part of the substrate luminescence signal, thus resulting in a modified substrate signal. The level of absorption depends on the NW-array geometry, making a deconvolution of the NW signal very difficult. By studying TRPL of substrate-only and as-grown NWs at 770 and 400 nm excitation wavelengths, we find a difference in spectral behavior with delay time and excitation power that can be used to assess whether the signal is dominated by the NWs. We find that the NW signal dominates with 400 nm excitation wavelength, where we observe two different types of excitation power dependence for the NWs capped with high and low Al composition shells. Finally, from the excitation power dependence of the peak TRPL signal, we extract an estimate of background carrier concentration in the NWs.</p>},
  articleno    = {505706},
  author       = {Dagyte, Vilgaile and Barrigón, Enrique and Zhang, Wei and Zeng, Xulu and Heurlin, Magnus and Otnes, Gaute and Anttu, Nicklas and Borgström, Magnus T.},
  issn         = {0957-4484},
  keyword      = {background doping,nanowire arrays,substrate signal,TRPL},
  language     = {eng},
  month        = {11},
  number       = {50},
  publisher    = {IOP Publishing},
  series       = {Nanotechnology},
  title        = {Time-resolved photoluminescence characterization of GaAs nanowire arrays on native substrate},
  url          = {http://dx.doi.org/10.1088/1361-6528/aa974b},
  volume       = {28},
  year         = {2017},
}