The role of surface depletion layer effects on the enhancement of the UV emission in ZnO induced by a nanostructured Al surface coating

Fiedler, S; Lee Cheong Lem, LO; Ton-That, C; Phillips, MR

The role of surface depletion layer effects on the enhancement of the UV emission in ZnO induced by a nanostructured Al surface coating

Fiedler, S Lee Cheong Lem, LO Ton-That, C

Phillips, MR

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Publisher:: ELSEVIER
Publication Type:: Journal Article
Citation:: Applied Surface Science, 2020, 504
Issue Date:: 2020-02-28

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Field	Value	Language
dc.contributor.author	Fiedler, S
dc.contributor.author	Lee Cheong Lem, LO
dc.contributor.author	Ton-That, C https://orcid.org/0000-0003-3276-1739
dc.contributor.author	Phillips, MR
dc.date.accessioned	2020-09-14T05:32:13Z
dc.date.available	2020-09-14T05:32:13Z
dc.date.issued	2020-02-28
dc.identifier.citation	Applied Surface Science, 2020, 504
dc.identifier.issn	0169-4332
dc.identifier.issn	1873-5584
dc.identifier.uri	http://hdl.handle.net/10453/142658
dc.description.abstract	© 2019 The UV enhancement of Al-coated ZnO single crystals with a wide range of carrier densities is systematically studied using depth-resolved cathodoluminescence and photoluminescence as well as valence band X-ray photoemission spectroscopy (VB-XPS). An up to 17-fold enhanced PL UV emission for Al-coated ZnO with the highest carrier density was measured, which falls to a 12-fold increase for the lowest carrier density. Depth-resolved cathodoluminescence measurements confirm that the enhancement is strongest near the Al-ZnO interface consistent with an increased UV emission due to an exciton-localized surface plasmon coupling mechanism. Correlative cathodoluminescence, photoluminescence and VB-XPS studies reveal that a number of additional effects related to the presence of the Al surface coating also contribute to the UV enhancement factor. These include increased UV enhancement due to the formation of a surface depletion layer induced by the Al coating, which also passivates competitive non-radiative surface recombination channels found in uncoated ZnO. Significantly, it was established that the magnitude of the emission enhancement factor can be raised in a controlled way by reducing the thickness of the depletion layer by increasing the carrier density. The contribution of these effects collectively provides an explanation for the large span of enhancement factors reported in the literature.
dc.language	English
dc.publisher	ELSEVIER
dc.relation	http://purl.org/au-research/grants/arc/DP150103317
dc.relation.ispartof	Applied Surface Science
dc.relation.isbasedon	10.1016/j.apsusc.2019.144409
dc.rights	info:eu-repo/semantics/embargoedAccess
dc.subject.classification	Applied Physics
dc.title	The role of surface depletion layer effects on the enhancement of the UV emission in ZnO induced by a nanostructured Al surface coating
dc.type	Journal Article
utslib.citation.volume	504
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - CCET - Centre for Clean Energy Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
pubs.organisational-group	/University of Technology Sydney
utslib.copyright.status	open_access	*
utslib.copyright.embargo	2022-02-02T00:00:00+1000Z
dc.date.updated	2020-09-14T05:31:54Z
pubs.publication-status	Published
pubs.volume	504

Abstract:

© 2019 The UV enhancement of Al-coated ZnO single crystals with a wide range of carrier densities is systematically studied using depth-resolved cathodoluminescence and photoluminescence as well as valence band X-ray photoemission spectroscopy (VB-XPS). An up to 17-fold enhanced PL UV emission for Al-coated ZnO with the highest carrier density was measured, which falls to a 12-fold increase for the lowest carrier density. Depth-resolved cathodoluminescence measurements confirm that the enhancement is strongest near the Al-ZnO interface consistent with an increased UV emission due to an exciton-localized surface plasmon coupling mechanism. Correlative cathodoluminescence, photoluminescence and VB-XPS studies reveal that a number of additional effects related to the presence of the Al surface coating also contribute to the UV enhancement factor. These include increased UV enhancement due to the formation of a surface depletion layer induced by the Al coating, which also passivates competitive non-radiative surface recombination channels found in uncoated ZnO. Significantly, it was established that the magnitude of the emission enhancement factor can be raised in a controlled way by reducing the thickness of the depletion layer by increasing the carrier density. The contribution of these effects collectively provides an explanation for the large span of enhancement factors reported in the literature.

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http://hdl.handle.net/10453/142658