Epitaxial UN and $\alpha$-U$_2$N$_3$ Thin Films

TL;DR

This study reports the first successful growth of epitaxial UN and U₂N₃ thin films, providing valuable samples for nuclear fuel research and fundamental studies of their properties.

Contribution

First-time growth of epitaxial UN and U₂N₃ thin films via reactive DC magnetron sputtering, enabling advanced research into nuclear fuel materials.

Findings

Films are [001] oriented and single domain

Lattice parameters: UN 4.895 Å, U₂N₃ 10.72 Å

Both films are stoichiometric

Abstract

Single crystal epitaxial thin films of UN and U$_2$N$_3$ have been grown for the first time by reactive DC magnetron sputtering. These films provide ideal samples for fundamental research into the potential accident tolerant fuel, UN, and U$_2$N$_3$, its intermediate oxidation product. Films were characterised using x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS), with XRD analysis showing both thin films to be [001] oriented and composed of a single domain. The specular lattice parameters of the UN and U$_2$N$_3$ films were found to be 4.895\,\AA{} and 10.72\,\AA{}, respectively, with the UN film having a miscut of 2.6\,$^\circ$. XPS showed significant differences in the N-1s peak between the two films, with area analysis showing both films to be stoichiometric.