High-Throughput Characterization of (FeCo_1-)₃O₄ Thin-Film Composition Spreads

Area of Science:

• Materials Science
• Thin Film Technology
• Solid State Chemistry

Background:

• Iron-cobalt oxides (Fe-Co-O) are complex materials with potential applications in electronics and catalysis.
• Controlling the composition and phase of Fe-Co-O thin films is crucial for tuning their properties.

Purpose of the Study:

• To fabricate continuous composition spreads of Fe-Co-O thin films.
• To investigate the influence of deposition temperature and composition on film properties.
• To explore the synthesis of specific spinel phases and their band gap variations.

Main Methods:

• Reactive cosputtering of Fe and Co targets in an Ar/O2 atmosphere.
• Deposition on fused silica and platinized Si/SiO2 substrates at temperatures from 300-700 °C.
• Characterization using high-throughput electron-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, and optical transmission spectroscopy.

Main Results:

• Continuous Fe-Co-O composition spreads with Fe content from 28 to 72 at.% were successfully fabricated.
• Fe2CoO4 and FeCo2O4 spinel phases were synthesized and stabilized across all deposition temperatures.
• Film microstructure, band gap (2.41-2.74 eV), and composition showed continuous variations.

Conclusions:

• Fe-Co-O thin films with tunable compositions and properties can be achieved through reactive cosputtering.
• The synthesized spinel phases exhibit a continuous variation in band gap with composition.
• These findings offer a pathway for developing novel Fe-Co-O based electronic materials.