Structural, Compositional, and Plasmonic Characteristics of Ti-Zr Ternary Nitride Thin Films Tuned by the Nitrogen Flow Ratio in Magnetron Sputtering.

Lianlian Chen,Zhi Wang,Zhaotan Jiang,Yinglan Li,Yujing Ran

doi:10.3390/nano10050829

Abstract

Ternary nitride gives high diversity and tunability of the plasmonic materials. In this work, highly crystallized ternary (Ti, Zr)N films were prepared by magnetron co-sputtering with different nitrogen gas flow ratio . The structural and plasmonic properties of the films tuned by were investigated. All the films are solid solutions of TiN and ZrN with a rocksalt structure and (111) preferred orientation. The films are nitrogen-overstoichiometric and the main defects are cation vacancies. Increased reduces the zirconium content, and therefore leads to the reduction of lattice constant and enhancement of the crystallinity. As increases, the screened plasma frequency decreases for the reduction of free electron density. The maximum of the energy loss spectra of (Ti, Zr)N films shifts to long-wavelength with increasing. The calculated electronic structure shows that increased nitrogen content enhances the electronic density of states of nitrogen and reduces that of metal, and therefore elevates the energy level at which interband transition is exited. The results show that (Ti, Zr)N films give a relatively high plasmonic quality in the visible and near-infrared region, and the film properties can be significantly tuned by the nitrogen content.

Highlights

For the optoelectronic devices in nanoscale, controlling the nano-dimensional interaction between light and matter has become a major scientific issue and a technological challenge [1,2]
The composition, crystal structure and the plasmonic characteristics can be effectively and widely tuned by nitrogen content, but some experimental laws are different from those of the films sputtered from nitride targets
It is in the expectation that the N-content of the films increases with Rn increasing, which can be explained by the reaction of the nitrogen atom and metal atoms

Summary

Introduction

For the optoelectronic devices in nanoscale, controlling the nano-dimensional interaction between light and matter has become a major scientific issue and a technological challenge [1,2]. Some metal nitrides have the conductivity comparable to noble metals, and their superior properties of mechanical, thermal and chemical stability bring them potential plasmonic applications in the extreme environment [6]. Their wide adjustability in plasmonic characteristics makes them one of the most likely choices for plasmonic application. The composition, crystal structure and the plasmonic characteristics can be effectively and widely tuned by nitrogen content, but some experimental laws are different from those of the films sputtered from nitride targets. This study demonstrates the potential plasmonic application of this ternary nitride and provides a method for adjusting plasmon performance through a wide range of nitrogen content for the preparation of ternary nitride films by magnetron sputtering

Experiments

Composition and Crystal Structure

Dielectric Function

Electronic Structure

Plasmonic Quality Factors

Conslusions