Imperial College London
Alternate

ProfessorNeilAlford

Faculty of Engineering, Department of Materials

Professor of Materials
 
 
 
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Contact

 

+44 (0)20 7594 6724n.alford

 
 
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Assistant

 

Ms Karen Murphy +44 (0)20 7594 3330

 
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Location

 

2..05 (in RSM)Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Braic:2017:10.1021/acsami.7b07660,
author = {Braic, L and Vasilantonakis, N and Mihai, A and Villar-Garcia, I and Fearn, S and Zou, B and Alford, N and Doiron, B and Oulton, R and Maier, S and Zayats, A and Petrov, P},
doi = {10.1021/acsami.7b07660},
journal = {ACS Applied Materials and Interfaces},
pages = {29857--29862},
title = {Titanium oxynitride thin films with tuneable double epsilon-near-zero behaviour for nanophotonic applications},
url = {http://dx.doi.org/10.1021/acsami.7b07660},
volume = {9},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Titanium oxynitride (TiOxNy) thin films are fabricated using reactive magnetron sputtering. The mechanism of their growth formation is explained, and their optical properties are presented. The films grown when the level of residual oxygen in the background vacuum was between 5 nTorr to 20 nTorr exhibit double epsilon-near-Zero (2-ENZ) behavior with ENZ1 and ENZ2 wavelengths tunable in the 700–850 and 1100–1350 nm spectral ranges, respectively. Samples fabricated when the level of residual oxygen in the background vacuum was above 2 × 10–8 Torr exhibit nonmetallic behavior, while the layers deposited when the level of residual oxygen in the background vacuum was below 5 × 10–9 Torr show metallic behavior with a single ENZ value. The double ENZ phenomenon is related to the level of residual oxygen in the background vacuum and is attributed to the mixture of TiN and TiOxNy and TiOx phases in the films. Varying the partial pressure of nitrogen during the deposition can further control the amount of TiN, TiOx, and TiOxNy compounds in the films and, therefore, tune the screened plasma wavelengths. A good approximation of the ellipsometric behavior is achieved with Maxwell–Garnett theory for a composite film formed by a mixture of TiO2 and TiN phases suggesting that double ENZ TiOxNy films are formed by inclusions of TiN within a TiO2 matrix. These oxynitride compounds could be considered as new materials exhibiting double ENZ in the visible and near-IR spectral ranges. Materials with ENZ properties are advantageous for designing the enhanced nonlinear optical response, metasurfaces, and nonreciprocal behavior.
AU  - Braic,L
AU  - Vasilantonakis,N
AU  - Mihai,A
AU  - Villar-Garcia,I
AU  - Fearn,S
AU  - Zou,B
AU  - Alford,N
AU  - Doiron,B
AU  - Oulton,R
AU  - Maier,S
AU  - Zayats,A
AU  - Petrov,P
DO  - 10.1021/acsami.7b07660
EP  - 29862
PY  - 2017///
SN  - 1944-8244
SP  - 29857
TI  - Titanium oxynitride thin films with tuneable double epsilon-near-zero behaviour for nanophotonic applications
T2  - ACS Applied Materials and Interfaces
UR  - http://dx.doi.org/10.1021/acsami.7b07660
UR  - http://hdl.handle.net/10044/1/52727
VL  - 9
ER  -
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