Low-temperature investigations of ion-induced amorphisation in silicon carbide nanowhiskers under helium irradiation
Low-temperature investigations of ion-induced amorphisation in silicon carbide nanowhiskers under helium irradiation
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DOI：
10.1016/j.apsusc.2019.143969
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发表时间：
2020-01-31
影响因子：
6.7
通讯作者：
Hinks, J. A.
中科院分区：
文献类型：
--
作者：
Aradi, E.;Lewis-Fell, J.;Hinks, J. A.
纳米多孔材料中丰富的自由表面可能在为去除辐射引起的缺陷提供理想的汇方面发挥重要作用。为了研究这些材料对辐射损伤的响应，4H-碳化硅 (SiC) 纳米晶须 (NW) 已被用来模拟纳米多孔 SiC 的单个韧带。使用氦离子辐照的原位透射电子显微镜（TEM），研究了纳米晶须的晶体到非晶态的转变作为辐照剂量和温度的函数。为了进行比较分析，使用 6 keV He 离子在 100 至 400 K 的温度和高达 50 dpa 的剂量下同时照射 NW 和 SiC 薄箔（块状 SiC 的模型系统）。与室温下辐照的箔片（大约 14%）相比，在 NW 中检测到由于非晶化而导致的相对较低的膨胀（大约 8%）。与箔片 (0.7 dpa) 相比，在低于室温的辐照下，在 NW 中观察到相对较高的非晶化临界剂量 (5 dpa)。对于在 200 K 以上（低于箔的临界温度（类似于 300 K））辐照的纳米线来说，完全避免了非晶化。纳米线表现出的非晶化的膨胀减少、临界剂量更高和临界温度更低表明箔的耐辐射性增强。
The abundant free surface in nanoporous materials may play a major role in providing ideal sinks for the removal of radiation-induced defects. To study the response of these materials to radiation damage, 4H-silicon carbide (SiC) nanowhiskers (NWs) have been used to model individual ligaments of nanoporous SiC. Using in-situ transmission electron microscopy (TEM) with helium ion irradiation, a crystalline-to-amorphous transformation of the nanowhiskers was investigated as a function of irradiation dose and temperature. For a comparative analysis, the NWs were irradiated simultaneously alongside SiC thin foils (model systems for bulk-like SiC) using 6 keV He ions at temperatures between 100 and 400 K and doses up to 50 dpa. Relatively-low swelling (similar to 8%) due to amorphisation was detected in the NWs compared to the foils (similar to 14%) irradiated at room temperature. A relatively-high critical dose for amorphisation (5 dpa) was observed in the NWs for irradiations below room temperature compared to the foils (0.7 dpa). Amorphisation was completely avoided for NWs irradiated above 200 K - lower than the critical temperature in the foils which was similar to 300 K. The reduced swelling, higher critical-dose and lower critical-temperature for amorphisation exhibited by the NWs indicate an enhancement in radiation resistance over the foils.