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Progress in research on one-dimensional nanomaterials irradiated by heavy ions by the Institute of Modern Physics
The mutual research of energetic heavy ions and macroscopic bulk materials has been carried out for many years, and the research results are widely used in the fields of material modification, nuclear material radiation resistance evaluation, and electronic component reinforcement. When the size of the bulk material is reduced to the nanometer level, its acoustics, electromagnetics, thermodynamics, and optics will all change significantly. This leads to the same irradiation effect as the bulk material under the same irradiation conditions. It's different. In order to study the radiation damage effects of metal nanomaterials, researchers from the Materials Research Center of the Institute of Modern Physics, Chinese Academy of Sciences took the one-dimensional nanomaterials prepared by the heavy ion track template method-gold nanowires as the research object, and carried out in-depth research on heavy ion The study of the interaction of one-dimensional nanomaterials reveals the basic physical process and damage mechanism of one-dimensional nanomaterials irradiated by heavy ions. The researchers used the heavy ions provided by the 320kV highly charged ion comprehensive experimental platform of the Institute of Modern Physics to irradiate gold nanowires of different diameters, and used scanning electron microscopes (SEM) and high resolution transmission electron microscopes (HRTEM) to irradiate gold nanowires before and after irradiation. The morphology and structure of gold nanowires were characterized and analyzed, and the radiation damage effects of heavy ions on gold nanowires were systematically studied. Studies have found that heavy ion irradiation can produce three types of crater-like structures with different morphologies on the surface of the nanowires, and the crater structures with different morphologies are directly related to the position of the heat peaks in the nanowires caused by heavy ions. When the thermal peak occurs several atomic layers below the surface of the nanowire, the molten gold in the thermal peak will be adsorbed on the surface of the nanowire through plastic flow, forming a crater-shaped structure; and when the thermal peak appears at a position deeper from the surface At this time, the volume expansion of the molten gold will generate a huge pressure to cause a micro-explosion in the area where the heat peak is located, leading to the eruption of the molten gold. When the kinetic energy of the ejected gold is less than the surface adsorption energy of the nanowires, it will be adsorbed on the nanowires to form craters with protruding particles; otherwise, craters without protruding particles will be formed. At the same time, a large number of sputtered gold nanoparticles were observed around the gold nanowires, and it was found that the average size of the sputtered particles increased as the diameter of the nanowires increased. In addition, the researchers studied the effect of heavy ion irradiation on the crystal structure of gold nanowires. A large number of stacking fault tetrahedral structures (SFT) were observed through HRTEM, and the SFT size distribution in the gold nanowires and the nuclear energy loss of incident ions were obtained. Relationship between. This research extends the research object of heavy ion irradiation from macroscopic bulk materials to one-dimensional nanomaterials, revealing the new characteristics of heavy ion irradiation based on nanomaterials. The research work was supported by the National Natural Science Foundation of China and the Youth Innovation Promotion Association of the Chinese Academy of Sciences. Related research results are published on Nanomaterials.
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