Metal nitride thin films for plasmonic devices


Metal nitride thin films for plasmonic devices

S. L. Zhu 1 , A. Gentle 1 , V. Keast 2 , M. B. Cortie 1

1 Institute for Nanoscale Technology, University of Technology Sydney, PO Box 123,

Broadway, NSW, 2007, Australia

2 School of Mathematical and Physical Sciences, University of Newcastle, Cnr King and Auckland Streets, Newcastle, NSW, 2300, Australia e:

The transition metal nitrides have gained significant attention for their potential technological applications. Besides their well-known hardness and tribological characteristics, they also have interesting electronic, magnetic and optical properties.

Titanium nitride can be prepared in a range of stoichiometries so that it is better designated as TiN


(where 0< x <0.43). It is already known that when x

0 the material can sustain surface plasmon polaritions in the visible and near-infrared region of the spectrum [1, 2]. Here we explore the optical properties of thin films with a wider range of stoichiometries and including samples that have been doped or alloyed with other transition metals. Magnetron sputtering was used to deposit thin films of these materials which were then characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), ellipsometry and X-ray diffraction. The flow ratios of argon and nitrogen relative to deposition power and the influence of the substrate temperature were also studied. The experimental work was supported by calculation of the dielectric functions of the materials using density functional theory.

We show that the dielectric function of TiN


is a sensitive function of the value of x which provides a way to tune the optical response. The performance of thin films of these materials approaches that of gold under some circumstances but they would obviously be far cheaper to manufacture. We expect that TiN


could be used in future designs of plasmonic devices and metamaterials.

We think Dr. Linda Xiao for assistance with the deposition and characterization. This work is supported by ARC Discovery project (120102545).


[1] M. B. Cortie, J. Giddings and A. Dowd, Nanotechnology 21 , 2010, 115201


[2] G. V. Naik, J. L. Schroeder, X. Ni, A. V. Kildishev, T. D. Sands, and A. Boltasseva,

Optical Materials Express , 2, 478,(2012)