The ion beam-induced bending of thin metal films represents a potent technique for fabricating three-dimensional structures using focused ion beam technology. This technique exhibits significant potential in the realm of micro and nano-scale structure fabrication for applications in various novel devices, such as plasmonic detectors. However, achieving greater control is imperative to ensure the reproducible fabrication of intricate structures. Here, we investigate mechanisms of bending and their dependence on conditions using molecular dynamics (MD) simulations for both monocrystalline and polycrystalline gold films. Our findings reveal the distinct differences in the bending behaviors between monocrystalline and polycrystalline films, as well as the significant dependence of bending on irradiation conditions that can be utilized for control purposes. The results show that mass transports are associated with defect formation and migrations, as well as migration of grain boundaries in the polycrystalline case, which play key roles. We observe a slow initial stage of film bending by following the commencement of irradiation, which is attributed to non-uniform stress fields from non-uniform defect generation; however, mass transport becomes increasingly important at higher doses. There is a strong interplay between this mass transport and grain boundaries, leading to differences in the behavior of monocrystalline and polycrystalline films.

中文翻译：

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镓离子辐照单晶和多晶薄膜弯曲的机理和控制

离子束引起的金属薄膜弯曲代表了使用聚焦离子束技术制造三维结构的有效技术。该技术在微米和纳米级结构制造领域表现出巨大的潜力，可应用于各种新颖的设备，例如等离子体探测器。然而，为了确保复杂结构的可重复制造，必须实现更大的控制。在这里，我们使用单晶和多晶金薄膜的分子动力学 (MD) 模拟研究弯曲机制及其对条件的依赖性。我们的研究结果揭示了单晶薄膜和多晶薄膜之间弯曲行为的明显差异，以及弯曲对可用于控制目的的辐照条件的显着依赖性。结果表明，质量传输与缺陷形成和迁移以及多晶情况下晶界的迁移有关，这起着关键作用。我们在照射开始后观察到薄膜弯曲的初始阶段很慢，这是由于不均匀缺陷产生产生的不均匀应力场所致；然而，在较高剂量下，质量运输变得越来越重要。这种传质和晶界之间存在很强的相互作用，导致单晶和多晶薄膜的行为存在差异。