Cargando…
Chemistry and Charge Trapping at the Interface of Silver and Ultrathin Layers of Zinc Oxide
[Image: see text] Zinc oxide, a wide-band-gap semiconductor, shows intriguing optoelectronic properties when coupled with Ag. Specifically, an absorbance band in the visible range that is not apparent in the separated materials emerges when the interface is formed. Interestingly, photoexcitation of...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2021
|
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8592502/ https://www.ncbi.nlm.nih.gov/pubmed/34628851 http://dx.doi.org/10.1021/acsami.1c11566 |
_version_ | 1784599476878442496 |
---|---|
author | Rahamim, M. Cohen, H. Edri, E. |
author_facet | Rahamim, M. Cohen, H. Edri, E. |
author_sort | Rahamim, M. |
collection | PubMed |
description | [Image: see text] Zinc oxide, a wide-band-gap semiconductor, shows intriguing optoelectronic properties when coupled with Ag. Specifically, an absorbance band in the visible range that is not apparent in the separated materials emerges when the interface is formed. Interestingly, photoexcitation of this “interface band” or band-to-band results in a counterintuitive photovoltaic response when a supra/sub-band-gap light is shone. To investigate the origin of this absorbance band and photovoltaic response, we studied in detail the energy-band alignment of ultrathin layers of ZnO (3–60 nm) with Ag. Our analysis indicated that an ‘electrostatic potential cliff’ is formed within the first 1–2 nm of ZnO. In addition, oxygen vacancies, presumably generated by Ag(x)O–Zn bonds, form mid-gap acceptor states within these first few nm. Both effects facilitate a valence band-to-defect state optical transition that is confined to the interface region. The second type of defects—hole-trap states associated with zinc hydroxide—are spread throughout the ZnO layer and dominate the supra-band-gap photovoltaic response. These findings have potential implications in emerging technologies such as photocatalytic Ag/ZnO heterostructures that will utilize the long-lived charges for chemical work or other optoelectronic applications. |
format | Online Article Text |
id | pubmed-8592502 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-85925022021-11-16 Chemistry and Charge Trapping at the Interface of Silver and Ultrathin Layers of Zinc Oxide Rahamim, M. Cohen, H. Edri, E. ACS Appl Mater Interfaces [Image: see text] Zinc oxide, a wide-band-gap semiconductor, shows intriguing optoelectronic properties when coupled with Ag. Specifically, an absorbance band in the visible range that is not apparent in the separated materials emerges when the interface is formed. Interestingly, photoexcitation of this “interface band” or band-to-band results in a counterintuitive photovoltaic response when a supra/sub-band-gap light is shone. To investigate the origin of this absorbance band and photovoltaic response, we studied in detail the energy-band alignment of ultrathin layers of ZnO (3–60 nm) with Ag. Our analysis indicated that an ‘electrostatic potential cliff’ is formed within the first 1–2 nm of ZnO. In addition, oxygen vacancies, presumably generated by Ag(x)O–Zn bonds, form mid-gap acceptor states within these first few nm. Both effects facilitate a valence band-to-defect state optical transition that is confined to the interface region. The second type of defects—hole-trap states associated with zinc hydroxide—are spread throughout the ZnO layer and dominate the supra-band-gap photovoltaic response. These findings have potential implications in emerging technologies such as photocatalytic Ag/ZnO heterostructures that will utilize the long-lived charges for chemical work or other optoelectronic applications. American Chemical Society 2021-10-09 2021-10-20 /pmc/articles/PMC8592502/ /pubmed/34628851 http://dx.doi.org/10.1021/acsami.1c11566 Text en © 2021 American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Rahamim, M. Cohen, H. Edri, E. Chemistry and Charge Trapping at the Interface of Silver and Ultrathin Layers of Zinc Oxide |
title | Chemistry
and Charge Trapping at the Interface of
Silver and Ultrathin Layers of Zinc Oxide |
title_full | Chemistry
and Charge Trapping at the Interface of
Silver and Ultrathin Layers of Zinc Oxide |
title_fullStr | Chemistry
and Charge Trapping at the Interface of
Silver and Ultrathin Layers of Zinc Oxide |
title_full_unstemmed | Chemistry
and Charge Trapping at the Interface of
Silver and Ultrathin Layers of Zinc Oxide |
title_short | Chemistry
and Charge Trapping at the Interface of
Silver and Ultrathin Layers of Zinc Oxide |
title_sort | chemistry
and charge trapping at the interface of
silver and ultrathin layers of zinc oxide |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8592502/ https://www.ncbi.nlm.nih.gov/pubmed/34628851 http://dx.doi.org/10.1021/acsami.1c11566 |
work_keys_str_mv | AT rahamimm chemistryandchargetrappingattheinterfaceofsilverandultrathinlayersofzincoxide AT cohenh chemistryandchargetrappingattheinterfaceofsilverandultrathinlayersofzincoxide AT edrie chemistryandchargetrappingattheinterfaceofsilverandultrathinlayersofzincoxide |