Multiphase strontium molybdate thin films for plasmonic local heating applications

TL;DR

This study investigates the thermal stability and oxidation resistance of SrMoO3 thin films, a promising plasmonic material, revealing degradation at high temperatures and a method to enhance stability via nitrogen annealing.

Contribution

It introduces a method of annealing in nitrogen to induce SrMoO4 formation, improving oxidation resistance of SrMoO3 thin films for high-temperature plasmonic applications.

Findings

Loss of metallic behavior at 500°C in air

Nitrogen annealing induces SrMoO4 phase

Nitrogen treatment suppresses oxidation at high temperatures

Abstract

In the search for alternative plasmonic materials SrMoO3 has recently been identified as possessing a number of desirable optical properties. Owing to the requirement for many plasmonic devices to operate at elevated temperatures however, it is essential to characterize the degradation of these properties upon heating. Here, SrMoO3 thin films are annealed in air at temperatures ranging from 75 - 500{\deg} C. Characterizations by AFM, XRD, and spectroscopic ellipsometry after each anneal identify a loss of metallic behaviour after annealing at 500{\deg} C, together with the underlying mechanism. Moreover, it is shown that by annealing the films in nitrogen following deposition, an additional crystalline phase of SrMoO4 is induced at the film surface, which suppresses oxidation at elevated temperatures.