Titanium oxynitride thin films with tuneable double epsilon-near-zero behaviour for nanophotonic applications
| Autor: | Brock Doiron, Neil McN. Alford, Anatoly V. Zayats, Rupert F. Oulton, Peter K. Petrov, Andrei P. Mihai, Bin Zou, Stefan A. Maier, Nikolaos Vasilantonakis, Laurentiu Braic, Lesley F. Cohen, Ignacio J. Villar Garcia, Sarah Fearn |
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| Přispěvatelé: | Engineering & Physical Science Research Council (E, The Leverhulme Trust, Engineering & Physical Science Research Council (EPSRC), Technology Strategy Board |
| Rok vydání: | 2017 |
| Předmět: |
Technology
Materials science 0306 Physical Chemistry (Incl. Structural) Materials Science Analytical chemistry 0904 Chemical Engineering chemistry.chemical_element Materials Science Multidisciplinary NONLINEARITY 02 engineering and technology titanium oxynitride epsilon near zero 01 natural sciences plasmonics Sputtering METAMATERIALS 0103 physical sciences NITRIDE General Materials Science ALTERNATIVE PLASMONIC MATERIALS Thin film Nanoscience & Nanotechnology OXIDES Deposition (law) 010302 applied physics COATINGS Science & Technology Partial pressure Plasma 021001 nanoscience & nanotechnology WAVELENGTHS cond-mat.mtrl-sci titanium nitride Wavelength chemistry thin films TIN nonlinear photonics RAY PHOTOELECTRON-SPECTROSCOPY Science & Technology - Other Topics GROWTH 0210 nano-technology Tin Titanium 0303 Macromolecular And Materials Chemistry |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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