Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells

<p dir="ltr">NiO alloyed with aluminum, Ni<sub>1</sub>−<sub>x</sub>Al<sub>x</sub>O, is analyzed in terms of its stoichiometry, electronic and transport properties, as well as interfacial band alignment with Si to evaluate its potential use as a hol...

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Main Author: S. Halilov (19672600) (author)
Other Authors: M. L. Belayneh (19672603) (author), M. A. Hossain (8962733) (author), A. A. Abdallah (19672606) (author), B. Hoex (19102583) (author), S. N. Rashkeev (19672609) (author)
Published: 2020
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_version_ 1864513505266237440
author S. Halilov (19672600)
author2 M. L. Belayneh (19672603)
M. A. Hossain (8962733)
A. A. Abdallah (19672606)
B. Hoex (19102583)
S. N. Rashkeev (19672609)
author2_role author
author
author
author
author
author_facet S. Halilov (19672600)
M. L. Belayneh (19672603)
M. A. Hossain (8962733)
A. A. Abdallah (19672606)
B. Hoex (19102583)
S. N. Rashkeev (19672609)
author_role author
dc.creator.none.fl_str_mv S. Halilov (19672600)
M. L. Belayneh (19672603)
M. A. Hossain (8962733)
A. A. Abdallah (19672606)
B. Hoex (19102583)
S. N. Rashkeev (19672609)
dc.date.none.fl_str_mv 2020-06-11T12:00:00Z
dc.identifier.none.fl_str_mv 10.1039/d0ra02982c
dc.relation.none.fl_str_mv https://figshare.com/articles/journal_contribution/Optimized_Ni_sub_1_x_sub_Al_sub_x_sub_O_hole_transport_layer_for_silicon_solar_cells/27021601
dc.rights.none.fl_str_mv CC BY 4.0
info:eu-repo/semantics/openAccess
dc.subject.none.fl_str_mv Engineering
Materials engineering
NiO (Nickel Oxide)
Aluminum Alloying
Hole Transport Layer (HTL)
p–i–n Type
Solar Cells
Stoichiometry
dc.title.none.fl_str_mv Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
dc.type.none.fl_str_mv Text
Journal contribution
info:eu-repo/semantics/publishedVersion
text
contribution to journal
description <p dir="ltr">NiO alloyed with aluminum, Ni<sub>1</sub>−<sub>x</sub>Al<sub>x</sub>O, is analyzed in terms of its stoichiometry, electronic and transport properties, as well as interfacial band alignment with Si to evaluate its potential use as a hole transport layer (HTL) in p–i–n type solar cells. The analysis is based on component material and slab structural simulations, as well as simulated and measured angle-resolved valence-band photoemission spectroscopy (PES) data, in order to reveal the best suitable stoichiometry. It is concluded that the ionization energy from the highest occupied states tends to increase with Al content as the simulated work function grows from 4.1 eV for pure NiO to 4.7 eV for heavily alloyed Al<sub>0</sub>.<sub>50</sub>Ni0.<sub>50</sub>O. The electronic structure as a function of the interface design between crystalline silicon and the transport layer is used to assess the band lineup and its correlation with the discontinuity of the affinities. The affinity rule is tested by evaluating the workfunctions of the component layers and justified best for a particular Ni-enriched interface design. Technology Computer-Aided Design (TCAD) device simulations show, that the band offset between oxide and crystalline silicon remains within the range of values to sustain a staggering alignment – a condition suitable for effective charge separation, similar to a situation in a tunneling diode. The self-energy of the hole carriers is estimated by contrasting simulated and measured photoemission data, which in the case of non-annealed Al-rich samples is shown to be an order of magnitude higher due to the disorder effects. The work functions derived from the measured PES data for the epitaxially grown oxide films with nearly identical alloy stoichiometry correlate well with the simulated values. The findings suggest that the optimal HTL is formed by starting with a pure Ni layer, followed by a graded doping Al<sub>x</sub>Ni<sub>1</sub>−<sub>x</sub>O, with x high at contact/oxide interface and low at the oxide/semiconductor.</p><h2>Other Information</h2><p dir="ltr">Published in: RSC Advances<br>License: <a href="https://creativecommons.org/licenses/by-nc/4.0/deed.en" target="_blank">https://creativecommons.org/licenses/by-nc/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1039/d0ra02982c" target="_blank">https://dx.doi.org/10.1039/d0ra02982c</a></p>
eu_rights_str_mv openAccess
id Manara2_fed55863630d73c2fc120fb019b2d9d7
identifier_str_mv 10.1039/d0ra02982c
network_acronym_str Manara2
network_name_str Manara2
oai_identifier_str oai:figshare.com:article/27021601
publishDate 2020
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rights_invalid_str_mv CC BY 4.0
spelling Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cellsS. Halilov (19672600)M. L. Belayneh (19672603)M. A. Hossain (8962733)A. A. Abdallah (19672606)B. Hoex (19102583)S. N. Rashkeev (19672609)EngineeringMaterials engineeringNiO (Nickel Oxide)Aluminum AlloyingHole Transport Layer (HTL)p–i–n TypeSolar CellsStoichiometry<p dir="ltr">NiO alloyed with aluminum, Ni<sub>1</sub>−<sub>x</sub>Al<sub>x</sub>O, is analyzed in terms of its stoichiometry, electronic and transport properties, as well as interfacial band alignment with Si to evaluate its potential use as a hole transport layer (HTL) in p–i–n type solar cells. The analysis is based on component material and slab structural simulations, as well as simulated and measured angle-resolved valence-band photoemission spectroscopy (PES) data, in order to reveal the best suitable stoichiometry. It is concluded that the ionization energy from the highest occupied states tends to increase with Al content as the simulated work function grows from 4.1 eV for pure NiO to 4.7 eV for heavily alloyed Al<sub>0</sub>.<sub>50</sub>Ni0.<sub>50</sub>O. The electronic structure as a function of the interface design between crystalline silicon and the transport layer is used to assess the band lineup and its correlation with the discontinuity of the affinities. The affinity rule is tested by evaluating the workfunctions of the component layers and justified best for a particular Ni-enriched interface design. Technology Computer-Aided Design (TCAD) device simulations show, that the band offset between oxide and crystalline silicon remains within the range of values to sustain a staggering alignment – a condition suitable for effective charge separation, similar to a situation in a tunneling diode. The self-energy of the hole carriers is estimated by contrasting simulated and measured photoemission data, which in the case of non-annealed Al-rich samples is shown to be an order of magnitude higher due to the disorder effects. The work functions derived from the measured PES data for the epitaxially grown oxide films with nearly identical alloy stoichiometry correlate well with the simulated values. The findings suggest that the optimal HTL is formed by starting with a pure Ni layer, followed by a graded doping Al<sub>x</sub>Ni<sub>1</sub>−<sub>x</sub>O, with x high at contact/oxide interface and low at the oxide/semiconductor.</p><h2>Other Information</h2><p dir="ltr">Published in: RSC Advances<br>License: <a href="https://creativecommons.org/licenses/by-nc/4.0/deed.en" target="_blank">https://creativecommons.org/licenses/by-nc/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1039/d0ra02982c" target="_blank">https://dx.doi.org/10.1039/d0ra02982c</a></p>2020-06-11T12:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.1039/d0ra02982chttps://figshare.com/articles/journal_contribution/Optimized_Ni_sub_1_x_sub_Al_sub_x_sub_O_hole_transport_layer_for_silicon_solar_cells/27021601CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/270216012020-06-11T12:00:00Z
spellingShingle Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
S. Halilov (19672600)
Engineering
Materials engineering
NiO (Nickel Oxide)
Aluminum Alloying
Hole Transport Layer (HTL)
p–i–n Type
Solar Cells
Stoichiometry
status_str publishedVersion
title Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
title_full Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
title_fullStr Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
title_full_unstemmed Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
title_short Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
title_sort Optimized Ni<sub>1−x</sub>Al<sub>x</sub>O hole transport layer for silicon solar cells
topic Engineering
Materials engineering
NiO (Nickel Oxide)
Aluminum Alloying
Hole Transport Layer (HTL)
p–i–n Type
Solar Cells
Stoichiometry