The overall objective of this effort is to establish the theoretical and experimental foundation for tip-directed nanoparticle assembly using surface-plasmon excitation. Specific research objectives include expanding understanding of (1) optical excitation, heating, and cooling of nanoparticle/nanoprobe systems; (2) melting, fusion, and evaporation of nanoparticles; and (3) factors involved in scaling up directed nano-assembly for manufacturing. The research approach exploits the unique optical and thermal properties of metallic nanoparticles. Specifically, certain metal nanoparticles can be selectively heated using optical excitation at their surface plasmon resonance wavelength. The presence of a sharp, nanoscale tip, under control of an atomic force microscope in this case, spatially localizes the excitation. Finally, nanoparticles melt at temperatures significantly below their bulk melting temperatures allowing fusion of the particles into desired structures and ultimately into active nanoscale devices. Both multi-physics simulations and tip-based assembly experiments will be conducted to determine the conditions required for optimal resolution, throughput, and reproducibility of the assembly process. The investigation of tip directed nanoparticle assembly will have a far reaching impact on the understanding of nanoscale electromagnetics and thermal transport. This new nano-manufacturing technique will have broad societal impact by enabling the production of active devices, with applications in fields such as computing, communications, and medicine, from nanoscale building blocks. In addition, this relatively simple and low-cost nano-assembly approach will make nano-manufacturing technology more widely accessible. In order to establish a highly-trained nanotechnology workforce, participants will receive extensive interdisciplinary training in nanoscale optics, thermal sciences, fabrication, microscopy, metrology, and modeling. Outstanding undergraduate participants will be drawn from the University of Kentucky?s Nanoscale Engineering Certificate Program (NECP) and the Honors Program on Nanotechnology. In addition, the project provides a foundation for nanotechnology and optics related outreach efforts to high schools students in both urban and Appalachian regions of Kentucky.
