The University of Southampton
University of Southampton Institutional Repository

Laterally modulating carrier concentration by ion irradiation in CdO thin films for mid-IR plasmonics

Laterally modulating carrier concentration by ion irradiation in CdO thin films for mid-IR plasmonics
Laterally modulating carrier concentration by ion irradiation in CdO thin films for mid-IR plasmonics
This report demonstrates tunable carrier densities in CdO thin films through local ion irradiation, providing lateral control of mid-IR optical properties. Ion-solid interactions produce donor-like defects that boost electron concentrations from the practical minimum of 2.5 × 1019 cm−3 to a maximum of 2.5 × 1020 cm−3 by metered ion exposure. This range is achieved using He, N, Ar, or Au ions at 1–2.8 MeV; when normalized by displacements per atom, all ion species produce comparable results. Since CdO is well-described by the Drude model, irradiation-tuned carrier densities directly alter the infrared dielectric function, and in turn, mid-infrared optical properties. Further, it is demonstrated that by combining irradiation with traditional lithography, CdO films expose to ions in the presence of 3-µm thick, patterned photoresist exhibit lateral carrier density profiles with ≈400-nm resolution. Scanning near-field optical microscopy reveals sharp optical interfaces with almost no companion contrast in surface morphology, microstructure, or crystallinity. Finally, CdO lateral homostructures supporting surface plasmon polaritons (SPPs) are demonstrated whose dispersion relation can be tuned through periodic patterning in a monolithic platform by simple nanofabrication. Numerical simulations show these polaritons result from strong coupling between excitations at CdO plasma frequencies and SPPs supported by the platinum substrate.
2195-1071
Cleri, Angela J.
3e6a5fb9-a6d7-41bd-869f-3afd842910fc
He, Mingze
0e9cf440-ee5d-483e-a1e4-097398bcc58d
Tolchin, Maxwell J.
d369e64b-938f-4784-87e5-bacbb70a6f93
Gubbin, Christopher
9a409ba4-380a-4cf8-bd48-a457eaefbef5
Lang, Eric
da794a4f-617e-4c3f-ae3b-773e853d48eb
Hattar, Khalid
650b92d6-2c06-4cbf-817c-458a655a8a67
De Liberato, Simone
5942e45f-3115-4027-8653-a82667ed8473
Caldwell, Joshua D.
4fa27289-4a00-4e6f-811c-a95054a8bc11
Maria, Jon-Paul
9f14edcc-e180-4e17-9d11-3afc7d00ccce
Cleri, Angela J.
3e6a5fb9-a6d7-41bd-869f-3afd842910fc
He, Mingze
0e9cf440-ee5d-483e-a1e4-097398bcc58d
Tolchin, Maxwell J.
d369e64b-938f-4784-87e5-bacbb70a6f93
Gubbin, Christopher
9a409ba4-380a-4cf8-bd48-a457eaefbef5
Lang, Eric
da794a4f-617e-4c3f-ae3b-773e853d48eb
Hattar, Khalid
650b92d6-2c06-4cbf-817c-458a655a8a67
De Liberato, Simone
5942e45f-3115-4027-8653-a82667ed8473
Caldwell, Joshua D.
4fa27289-4a00-4e6f-811c-a95054a8bc11
Maria, Jon-Paul
9f14edcc-e180-4e17-9d11-3afc7d00ccce

Cleri, Angela J., He, Mingze, Tolchin, Maxwell J., Gubbin, Christopher, Lang, Eric, Hattar, Khalid, De Liberato, Simone, Caldwell, Joshua D. and Maria, Jon-Paul (2024) Laterally modulating carrier concentration by ion irradiation in CdO thin films for mid-IR plasmonics. Advanced Optical Materials. (doi:10.1002/adom.202401009).

Record type: Article

Abstract

This report demonstrates tunable carrier densities in CdO thin films through local ion irradiation, providing lateral control of mid-IR optical properties. Ion-solid interactions produce donor-like defects that boost electron concentrations from the practical minimum of 2.5 × 1019 cm−3 to a maximum of 2.5 × 1020 cm−3 by metered ion exposure. This range is achieved using He, N, Ar, or Au ions at 1–2.8 MeV; when normalized by displacements per atom, all ion species produce comparable results. Since CdO is well-described by the Drude model, irradiation-tuned carrier densities directly alter the infrared dielectric function, and in turn, mid-infrared optical properties. Further, it is demonstrated that by combining irradiation with traditional lithography, CdO films expose to ions in the presence of 3-µm thick, patterned photoresist exhibit lateral carrier density profiles with ≈400-nm resolution. Scanning near-field optical microscopy reveals sharp optical interfaces with almost no companion contrast in surface morphology, microstructure, or crystallinity. Finally, CdO lateral homostructures supporting surface plasmon polaritons (SPPs) are demonstrated whose dispersion relation can be tuned through periodic patterning in a monolithic platform by simple nanofabrication. Numerical simulations show these polaritons result from strong coupling between excitations at CdO plasma frequencies and SPPs supported by the platinum substrate.

Text
Irradiation_manuscript - Accepted Manuscript
Available under License Creative Commons Attribution.
Download (838kB)
Text
Advanced Optical Materials - 2024 - Cleri - Laterally Modulating Carrier Concentration by Ion Irradiation in CdO Thin Films - Version of Record
Download (6MB)

More information

e-pub ahead of print date: 24 September 2024

Identifiers

Local EPrints ID: 494451
URI: http://eprints.soton.ac.uk/id/eprint/494451
ISSN: 2195-1071
PURE UUID: be73e943-aefa-4135-85d8-8bff40ded217
ORCID for Simone De Liberato: ORCID iD orcid.org/0000-0002-4851-2633

Catalogue record

Date deposited: 08 Oct 2024 16:47
Last modified: 09 Oct 2024 01:50

Export record

Altmetrics

Contributors

Author: Angela J. Cleri
Author: Mingze He
Author: Maxwell J. Tolchin
Author: Christopher Gubbin
Author: Eric Lang
Author: Khalid Hattar
Author: Joshua D. Caldwell
Author: Jon-Paul Maria

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×