Oxygen Diffusion Study Published in Nano Letters

Understanding the behavior of oxygen is critical for the operation of energy storage, sensors, and other technologies, particularly in highly corrosive environments. In our latest study in Nano Letters, led by Tiffany Kaspar, we explore oxygen exchange in Fe2O3 / Cr2O3 interfaces using a unique oxygen labeling approach. These results she light on the kinetic and thermodynamic drivers for oxygen migration in extreme conditions.

From the abstract:

Thin film deposition from the vapor phase is a complex process involving adatom adsorption, movement, and incorporation into the growing film. Here, we present quantitative experimental data that reveals anion intermixing over long length scales during the deposition of epitaxial Fe2O3 and Cr2O3 films and heterostructures by oxygen-plasma-assisted molecular beam epitaxy. We track this diffusion by incorporating well-defined tracer layers containing 18O and/or 57Fe and measure their redistribution on the nanometer scale with atom probe tomography. Molecular dynamics simulations suggest potential intermixing events, which are then examined via nudged elastic band calculations. We reveal that adatoms on the film surface act to “pull up” subsurface O and Fe. Subsequent ring-like rotation mechanisms involving both adatom and subsurface anions then facilitate their mixing. In addition to film deposition, these intermixing mechanisms may be operant during other surface-mediated processes such as heterogeneous catalysis and corrosion.

To view the manuscript, visit: http://doi.org/10.1021/acs.nanolett.2c01678

To download the article directly, click here.