Latent Tracks in Ion-Irradiated LiTaO3 Crystals: Damage Morphology Characterization and Thermal Spike Analysis

Structure Formation and Regulation of Au Nanoparticles in LiTaO3 by Ion Beam and Thermal Annealing Techniques

The size uniformity and spatial dispersion of nanoparticles (NPs) formed by ion implantation must be further improved due to the characteristics of the ion implantation method. Therefore, specific swift heavy ion irradiation and thermal annealing are combined in this work to regulate the size and spatial distributions of embedded Au NPs formed within LiTaO₃ crystals. Experimental results show that small NPs migrate to deeper depths induced by 656 MeV Xe³⁵⁺ ion irradiation. During thermal annealing, the growth of large Au NPs is limited due to the reductions in the number of small Au NPs, and the migrated Au NPs aggregate at deeper depths, resulting in a more uniform size distribution and an increased spatial distribution of Au NPs. The present work presents a novel method to modify the size and spatial distributions of embedded NPs.

Thermal Spike Responses and Structure Evolutions in Lithium Niobate on Insulator (LNOI) under Swift Ion Irradiation

Irradiating solid materials with energetic ions are extensively used to explore the evolution of structural damage and specific properties in structural and functional materials under natural and artificial radiation environments. Lithium niobate on insulator (LNOI) technology is revolutionizing the lithium niobate industry and has been widely applied in various fields of photonics, electronics, optoelectronics, etc. Based on 30 MeV 35Cl and 40Ar ion irradiation, thermal spike responses and microstructure evolution of LNOI under the action of extreme electronic energy loss are discussed in detail. Combining experimental transmission electron microscopy characterizations with numerical calculations of the inelastic thermal spike model, discontinuous and continuous tracks with a lattice disorder structure in the crystalline LiNbO3 layer and recrystallization in the amorphous SiO2 layer are confirmed, and the ionization process via energetic ion irradiation is demonstrated to inherently connect energy exchange and temperature evolution processes in the electron and lattice subsystems of LNOI. According to Rutherford backscattering/channeling spectrometry and the direct impact model, the calculated track damage cross–section is further verified, coinciding with the experimental observations, and the LiNbO3 layer with a thickness of several hundred nanometers presents track damage behavior similar to that of bulk LiNbO3. Systematic research into the damage responses of LNOI is conducive to better understanding and predicting radiation effects in multilayer thin film materials under extreme radiation environments, as well as to designing novel multifunctional devices.