Fundamental Investigations in Femtosecond Laser-based Additive Manufacturing with Functional Nanomaterials

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With the coming era of the Internet-of-Things (IoT), there is an increasing need for miniaturized smart devices, such as smart sands, tags, and wearable/implantable devices, for various biomedical and environmental monitoring applications. Many critical components in these devices, such as sensors, antennas, inter-connects and batteries are not compatible with conventional Integrated Circuits (IC) processes used in the semiconductor industry. In addition, many devices need to be customized for their specific target applications, which could require three-dimensional nanostructures, heterogeneous materials integration, miniaturized form factor, and specified sensitivity, power density and life times. It is difficult for conventional semiconductor manufacturing foundries to accommodate these customized specifications due to the lack of flexibility in process and material choices. Micro and nanoscale additive manufacturing has the potential to meet such requirements. However, a technical breakthrough is still needed in this area to enable additive manufacturing of functional components with nanoscale resolution, quality and reliability commensurate with IC fabricated devices. This award supports fundamental research to form the knowledge base for development of nanoscale additive manufacturing (Nano-AM) processes for direct manufacturing of nano-devices. Multiple disciplines are involved in this research including nanomanufacturing, laser-nanomaterial interaction, surface science, and multiscale transport phenomena. Results from this research will enhance the U.S. competence in advanced manufacturing industry by providing paradigm-changing manufacturing technique in the era of IoT. The integration of the research results into curriculum development, undergraduate and minority students research opportunities and hands-on projects for K-12 students will enhance the students' knowledge and foster innovation in advanced manufacturing.Current nanoscale additive manufacturing is limited by the lack of capability to fabricate 3D nonpolymer functional devices. To overcome this limit, this research employs non-polymer (metal, semiconductor and dielectric) nanomaterials as building blocks and aims at understanding and exploiting unique behaviors of these nanomaterials under ultrafast laser excitation to enable 3D Nano-AM processes. Firstly, fundamental mechanisms leading to femtosecond laser induced ionization and surface modification of nanomaterials will be explored. Secondly, the correlations between laser excitation (ionization and modification) and induced nanomaterial assembly, deposition and sintering behaviors will be established. Multiscale modeling and simulations (Ab initio, classical Molecular Dynamics and Brownian Dynamics) will be performed to understand experimental results over different temporal and spatial scales. Finally, a physics-based model relating nanomaterials properties, laser excitation conditions with the morphology and properties of manufactured nanostructures will be developed.