Multi-wavelength emission through self-induced defects in GaZnO microrods

Rahman, MA; Ali, S; Phillips, MR; Ton-That, C

Multi-wavelength emission through self-induced defects in GaZnO microrods

Rahman, MA Ali, S Phillips, MR Ton-That, C

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Publisher:: Elsevier BV
Publication Type:: Journal Article
Citation:: Journal of Alloys and Compounds, 2021, pp. 162693-162693
Issue Date:: 2021-01-01

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Field	Value	Language
dc.contributor.author	Rahman, MA
dc.contributor.author	Ali, S
dc.contributor.author	Phillips, MR
dc.contributor.author	Ton-That, C https://orcid.org/0000-0003-3276-1739
dc.date.accessioned	2021-12-09T11:16:43Z
dc.date.available	2021-12-09T11:16:43Z
dc.date.issued	2021-01-01
dc.identifier.citation	Journal of Alloys and Compounds, 2021, pp. 162693-162693
dc.identifier.issn	0925-8388
dc.identifier.uri	http://hdl.handle.net/10453/152228
dc.description.abstract	Multi-wavelength emission in wide bandgap semiconductors is commonly achieved through ternary alloying or quantum size effects. However, multi-wavelength emission within a single microstructure is highly challenging using these approaches. Here, we demonstrate that the luminescence wavelength within individual GaZnO microrods can be tailored via defect engineering. Fast chemical vapor growth of oxygen-rich ZnO microrods with Ga2O3 as an additive in the ZnO vapour leads to formation of a tapered morphology with graded distribution of Ga dopants, while the Ga incorporation does not significantly alter their crystal structure. With increasing Ga content from 1 to 6 at% from tip to base, the GaZnO microrods increase in diameter towards the substrate in accordance with the birth-and-spread mechanism. The local near-band-edge emission within single ZnO microrods, analyzed by nanoscale cathodoluminescence spectroscopy, exhibits a red shift of ~0.6 eV with increasing Ga content and exhibits signature characteristics of an excitonic emission. Density Functional Theory calculations reveal that the variation in the emission wavelength arises from bandgap narrowing due to the merging of the electronic states of Ga defect complexes with ZnO energy bands. The experimental and theoretical results demonstrate (i) the utility of using the self-regulation of defect compensation effects for band gap engineering and (ii) the possibility of multi-wavelength light sources within individual microrods.
dc.language	en
dc.publisher	Elsevier BV
dc.relation	http://purl.org/au-research/grants/arc/DP150103317
dc.relation	http://purl.org/au-research/grants/arc/DP210101146
dc.relation.ispartof	Journal of Alloys and Compounds
dc.relation.isbasedon	10.1016/j.jallcom.2021.162693
dc.rights	info:eu-repo/semantics/embargoedAccess
dc.subject	0204 Condensed Matter Physics, 0912 Materials Engineering, 0914 Resources Engineering and Extractive Metallurgy
dc.subject.classification	Materials
dc.title	Multi-wavelength emission through self-induced defects in GaZnO microrods
dc.type	Journal Article
utslib.for	0204 Condensed Matter Physics
utslib.for	0912 Materials Engineering
utslib.for	0914 Resources Engineering and Extractive Metallurgy
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
utslib.copyright.status	open_access	*
utslib.copyright.embargo	2024-02-29T00:00:00+1000Z
dc.date.updated	2021-12-09T11:16:42Z
pubs.publication-status	Published

Abstract:

Multi-wavelength emission in wide bandgap semiconductors is commonly achieved through ternary alloying or quantum size effects. However, multi-wavelength emission within a single microstructure is highly challenging using these approaches. Here, we demonstrate that the luminescence wavelength within individual GaZnO microrods can be tailored via defect engineering. Fast chemical vapor growth of oxygen-rich ZnO microrods with Ga2O3 as an additive in the ZnO vapour leads to formation of a tapered morphology with graded distribution of Ga dopants, while the Ga incorporation does not significantly alter their crystal structure. With increasing Ga content from 1 to 6 at% from tip to base, the GaZnO microrods increase in diameter towards the substrate in accordance with the birth-and-spread mechanism. The local near-band-edge emission within single ZnO microrods, analyzed by nanoscale cathodoluminescence spectroscopy, exhibits a red shift of ~0.6 eV with increasing Ga content and exhibits signature characteristics of an excitonic emission. Density Functional Theory calculations reveal that the variation in the emission wavelength arises from bandgap narrowing due to the merging of the electronic states of Ga defect complexes with ZnO energy bands. The experimental and theoretical results demonstrate (i) the utility of using the self-regulation of defect compensation effects for band gap engineering and (ii) the possibility of multi-wavelength light sources within individual microrods.

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http://hdl.handle.net/10453/152228