Illustrated are combined effects of energy loss to electrons and atomic nuclei by an ion. Electronic energy loss results in a concentric thermal spike along the ion path (depicted by arrow), while energy loss to atomic nuclei results in atomic collisions that displace atoms creating damage (different atom species depicted by spheres of different colors).
An invited review on latest advances in ion beam modification of materials provides conclusive evidence that energy loss by energetic ions to electrons (ionization) can lead to either self-healing of radiation damage created by atomic collisions or contribute to radiation damage. Hybrid computational methods that model the effects of energy transfer from electrons to atomic nuclei are experimentally validated. These findings have significant implications because of the evolving use of ion beams to synthesize and functionalize materials or mimic the response of materials to extreme radiation environments.
Ionization-induced self-healing provides a novel approach to: (1) improve the quality of epitaxial films for devices and surface barrier coatings for harsh environments; (2) non-thermally heal ion-implantation damage during chip manufacturing; and (3) develop radiation-tolerant materials for nuclear, high-energy accelerator and space applications. Ionization-induced damage production can be exploited over a wide range of energies to create: (1) novel defect states and structures far from equilibrium; (2) nanopores; (3) unique nanostructures; and (4) new functionalities in materials.
W. J. Weber, D. M. Duffy, L. Thomé, and Y. Zhang, “The role of electronic energy loss in ion beam modification of materials,” Curr. Opin. Solid State Mater. Sci.19, 1 (2015). DOI: 10.1016/j.cossms.2014.09.003