Radiation-Induced Defects in Ion-Implanted Crystals

Ion implantation introduces energetic ions into a crystal lattice, displacing atoms and creating point defects—vacancies and interstitials—collectively known as Frenkel defects. These primary defects can cluster into extended dislocation loops and colour centres, altering optical, electrical and mechanical properties. Subsequent thermal annealing drives defect migration and recombination, reshaping the defect landscape and governing long-term material performance. Advanced electron microscopy, spectroscopy and atomistic simulations have revealed defect formation pathways in materials such as silicon carbide, corundum and magnesium aluminate spinel. Understanding the interplay between defect mobility, charge state and local chemistry is essential for designing radiation-tolerant semiconductors, ceramics for fusion diagnostics, and optical components in harsh environments. Control over defect populations enables tuning of luminescence, absorption and strength, with direct applications in microelectronics, nuclear reactors and space technology.

Research from Nature Portfolio

Recent studies have characterised the thermal stability and recombination kinetics of primary Frenkel defects in corundum, revealing two distinct oxygen interstitial species—neutral atoms and negatively charged ions—that coexist with F-type colour centres. Detailed analysis of annealing profiles and diffusion parameters has provided critical input for predictive models of defect-induced reactions and material tolerance under neutron irradiation. In magnesium aluminate spinel, investigations of electron and proton irradiation effects have demonstrated that migration energy and pre-exponential diffusion factors are strongly correlated, in line with the Meyer–Neldel rule, across single-crystal and transparent ceramic forms. These findings have advanced the understanding of defect recombination as a bimolecular reaction, facilitating the design of spinel-based optical materials for harsh radiation environments.

Radiation-Induced Defects in Ion-Implanted Crystals publication trend

The graph below shows the total number of articles in radiation-induced defects in ion-implanted crystals across all publications each year (not limited to Nature Index journals).

Technical terms

Frenkel defect: A vacancy and its corresponding interstitial created when an atom is displaced from its lattice site.

Colour centre (F-centre): An electron trapped at an anion vacancy that produces characteristic optical absorption.

Interstitial: An atom occupying a non-lattice site within the crystal structure.

Vacancy: A missing atom at a regular lattice position.

Thermal annealing: Heating a material to promote defect migration and recombination.

Bimolecular reaction: A process in which two mobile defects encounter and annihilate each other.

References

1. Distinctive features of diffusion-controlled radiation defect recombination in stoichiometric magnesium aluminate spinel single crystals and transparent polycrystalline ceramics. Scientific Reports (2020).
2. Evidence for the formation of two types of oxygen interstitials in neutron-irradiated α-Al2O3 single crystals. Scientific Reports (2021).
3. Paramagnetic Defects and Thermoluminescence in Irradiated Nanostructured Monoclinic Zirconium Dioxide. Materials (2022).
4. Optical Characteristics of MgAl2O4 Single Crystals Irradiated by 220 MeV Xe Ions. Materials (2023).
5. Comparative study of radiation-induced damage in magnesium aluminate spinel by means of IL, CL and RBS/C techniques. Physics and Chemistry of Minerals (2016).