Abstract Focused Electron Beam Induced Processing (FEBIP) is a powerful tool for the “direct-write” of nanomaterials with the possibility of atomistic control on suspended 2D material substrates. FEBIP capabilities have been significantly expanded by using a localized jet-based delivery of precursors, and especially when a thermally energized supersonic micro-jet enhances the delivery of mass flux along with controlling the far-from-equilibrium thermodynamic state of adsorbed adatoms. The possibilities of growing nanomaterials with “dialed-in” composition with ultra-high growth rates and aspect ratios up to 100:1 have been demonstrated using the supersonic micro-jet-FEBIP. Bringing this scientific discovery to the level of maturity required for practical applications in additive nanomanufacturing requires simulation tools that are capable of capturing the complex flow physics of micro-jet-substrate interactions that bridge a wide range of flow regimes from the high-density gas micro-jet expanding into the vacuum environment of FEBIP. To address this significant computational challenge, a new approach has been developed and described in this work for a multiscale adaptive DSMC (Direct Simulation Monte Carlo) algorithm to predict the micro-jet gas dynamics in an FEBIP environment, spanning the full range of flow regimes from low Knudsen (Kn) number O(0.01) continuum flow to high Kn of O(10) for the molecular flow within a unified computational framework. The fundamental principles of the adaptive DSMC algorithm are described, its viability as a DSMC technique is demonstrated, and computational improvements for the benchmark cases are discussed in the context of advancing 3D nanofabrication with FEBIP. Ultimately, combining the first principle simulations via adaptive DSMC with the complementary experimental data will enable the creation of the powerful CAD tools for in silico design and optimal operation of micro-jet-FEBIP.

中文翻译：

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自适应模拟使超音速微射流前驱体纳米材料的电子束加工的计算设计成为可能

摘要 聚焦电子束诱导处理 (FEBIP) 是纳米材料“直接写入”的强大工具，可以对悬浮的 2D 材料基板进行原子控制。通过使用基于局部射流的前体传递，FEBIP 的能力得到了显着扩展，特别是当热能超音速微射流增强质量通量的传递并控制吸附原子的远离平衡的热力学状态时。已经使用超音速微喷射 FEBIP 证明了生长具有“拨入”成分的纳米材料的可能性，该纳米材料具有超高的增长率和高达 100:1 的纵横比。将这一科学发现提升到增材纳米制造实际应用所需的成熟水平，需要能够捕捉微射流-基板相互作用的复杂流动物理学的模拟工具，这些相互作用将各种流态与高密度气体微观相连接。 -jet 扩展到 FEBIP 的真空环境中。为了解决这一重大的计算挑战，在这项工作中开发并描述了一种新方法，用于多尺度自适应 DSMC（直接模拟蒙特卡罗）算法，以预测 FEBIP 环境中的微射流气体动力学，跨越整个流态在统一计算框架内，从低 Knudsen (Kn) 数 O(0.01) 连续流到高 Kn 的 O(10) 分子流。描述了自适应 DSMC 算法的基本原理，展示了其作为 DSMC 技术的可行性，并在使用 FEBIP 推进 3D 纳米制造的背景下讨论了基准案例的计算改进。最终，将通过自适应 DSMC 的第一原理模拟与补充实验数据相结合，将能够创建强大的 CAD 工具，用于微喷射 FEBIP 的计算机设计和优化操作。