Speaker
Description
Additive manufacturing of nanoscale structures on a myriad of substrate types and surface morphologies stands as a prominent distinguishing feature of Focused Electron Beam Induced Deposition (FEBID) and Focused Ion Beam Induced Deposition (FIBID). Beyond the mere creation of bulky, planar, and simplistic pillar geometries, the controlled fabrication of intricate 3D nano-architectures has catalyzed a revolution in this realm of nanofabrication. That stems from its unparalleled prowess in design complexity, predicta-bility, reliability, feature sizes, and functional variability, which strongly improved over the last decade. However, the aspect of functionality often grapples with challenges posed by incomplete precursor dis-sociation, resulting in infamously high carbon contents that can diminish or entirely mask the intended functionalities upon initial fabrication. To leverage material quality and precisely tailor them to applica-tion requirements, post-processing techniques such as thermal treatments, exposure to gases, and/or irradiation with photons/electrons/ions prove indispensable as successfully demonstrated by many dif-ferent studies. While conventionally applied to the entire FEBID object in the past, we now embark on the next logical progression by introducing a paradigm shift: selective area modification, dubbed as func-tional imprinting. This innovative approach allows for the integration of functional regions boasting di-verse designs within the surrounding pristine material, thereby serving as a scaffold with varied proper-ties tailored for distinct purposes, e.g. embedding of plasmonically active elements in a flexible design.
In this contribution, we delve into two innovative post-processing methodologies, both harnessing the implications of a focused electron beam together with its complex behavior in solid materials for dynamic shape imprinting. Both concepts, however, use the local instead of a global application to the deposit of interest, which opens up new possibilities. The first concept, electron beam curing (EBC), involves sub-jecting deposits to an electron beam within vacuum conditions with no precursor gas present. This tech-nique offers a spectrum of possibilities, ranging from inducing statistical grain growth for electric conduc-tivity refinement, to manipulating the carbonaceous matrix with mechanical implications, and even achieving asymmetric stress-strain for the controlled bending of 3D objects, surpassing conventional fabrication constraints. As for the second approach, electron exposure in low-pressure, room tempera-ture water vapor serves to eliminate residual carbon from original deposits. Here, we meticulously assess this methodology by orchestrating local material transfer from pristine AuC$_X$ composition into pure gold, meticulously exploring design potentials, intrinsic limitations, and functional attributes of the transformed areas. The latter shows plasmonic activities with high lateral resolution as discussed in this contribution. Through these endeavors, we establish the groundwork for advanced local material tuning of FEBID/FIBID materials, potentially heralding novel application vistas at the nanoscale.