Temperature-dependent void formation and growth at ion-irradiated nanocrystalline CeO2–Si interfaces

Ceria is a thermally stable ceramic that has numerous applications in the nuclear industry, including use in nuclear fuels and waste forms. Recently, interest has surged in nanostructured ceria due to its increased mechanical properties and electronic conductivity in comparison with bulk ceria and its ability to self-heal in response to energetic ion bombardment. Here, nanocrystalline ceria thin films grown over a silicon substrate are irradiated to fluences of up to ∼4×1016ions/cm2 under different irradiation conditions: with differing ion species (Si+ and Ni+), different ion energies (1.0–1.5MeV), and at varying temperatures (160–600K). While the nanocrystalline ceria is found to exhibit exceptional radiation resistance under all tested conditions, severe ion irradiation-induced mixing, void formation, and void growth are observed at the ceria/silicon interface, with the degree of damage proving to be temperature dependent.