Titanium Oxynitride Thin Films with Tunable Double Epsilon-Near-Zero Behavior for Nanophotonic Applications

被引：95

作者：

Braic, Laurentiu ^{[1
]}

Vasilantonakis, Nikolaos ^{[2
]}

Mihai, Andrei ^{[1
]}

Garcia, Ignacio Jose Villar ^{[1
]}

Fearn, Sarah ^{[1
]}

Zou, Bin ^{[1
]}

Alford, Neil McN. ^{[1
]}

Doiron, Brock ^{[3
]}

Oulton, Rupert F. ^{[3
]}

Maier, Stefan A. ^{[3
]}

Zayats, Anatoly V. ^{[2
]}

Petrov, Peter K. ^{[1
]}

机构：

[1] Imperial Coll London, Dept Mat, Prince Consort Rd, London SW7 2BP, England

[2] Kings Coll London, Dept Phys, London WC2R 2LS, England

[3] Imperial Coll London, Dept Phys, Prince Consort Rd, London SW7 2AZ, England

来源：

ACS APPLIED MATERIALS & INTERFACES | 2017年 / 9卷 / 35期

基金：

英国工程与自然科学研究理事会;

关键词：

plasmonics; titanium nitride; titanium oxynitride; thin films; epsilon near zero; nonlinear photonics; ALTERNATIVE PLASMONIC MATERIALS; NITRIDE; TIN; NONLINEARITY; METAMATERIAL; INDEX;

D O I：

10.1021/acsami.7b07660

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

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 x 10(-8) Torr exhibit nonmetallic behavior, while the layers deposited when the level of residual oxygen in the background vacuum was below 5 X 10(-9) Torr show metallic 4 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.

引用

页码：29857 / 29862

页数：6