Nanoporous Morphogenesis in Amorphous Carbon Layers: Experiments and Modeling on Energetic Ion Induced Self‐Organization

Abstract

Nanoporous amorphous carbon constitutes a highly relevant material for a multitude of applications ranging from energy to environmental and biomedical systems. In the present work, it is demonstrated experimentally how energetic ions can be utilized to tailor porosity of thin sputter deposited amorphous carbon films. The physical mechanisms underlying self-organized nanoporous morphogenesis are unraveled by employing extensive molecular dynamics and phase field models across different length scales. It is demonstrated that pore formation is a defect induced phenomenon, in which vacancies cluster in a spinodal decomposition type of self-organization process, while interstitials are absorbed by the amorphous matrix, leading to additional volume increase and radiation induced viscous flow. The proposed modeling framework is capable to reproduce and predict the experimental observations from first principles and thus opens the venue for computer assisted design of nanoporous frameworks.

Self-Assembly and the Properties of Micro-Mesoporous Carbon

“…Although amorphous carbon lacks the pore structure present in NPCs, it shares a similar chemical environment, allowing us to gain insights into some of the locality-dependent chemistry of NPCs. 19,61,62 We constructed an amorphous carbon model with a density of 0.75 g/cm 3 . The surface slab was created by increasing the z-axis by 15 Å.…”

“…The rationale behind using surface models of amorphous carbon is that they provide numerous representative sites that are likely to occur on the surfaces of NPCs, as illustrated in Figure . Although amorphous carbon lacks the pore structure present in NPCs, it shares a similar chemical environment, allowing us to gain insights into some of the locality-dependent chemistry of NPCs. ,, …”

Subnanoscale Ion Beam Modification-Assisted Smoothing of Heterostructure Surfaces

“…The morphology of different materials under the same beam parameters was found to be significantly varied, and after ion beam processing, the surface quality of different phases of the same material (such as crystalline and amorphous phases) was also different. 9,10 As a result, the optimization parameters of the ion beam process vary depending on the type of material. GC is a typical heterostructure containing both residual glass phases (GPs) and one or more embedded ceramic phases (CPs).…”

“…Some early studies investigated how low-energy ion beams affect the evolution of surface morphology. The morphology of different materials under the same beam parameters was found to be significantly varied, and after ion beam processing, the surface quality of different phases of the same material (such as crystalline and amorphous phases) was also different. , As a result, the optimization parameters of the ion beam process vary depending on the type of material.…”