LASER - LIQUID METAL INTERACTION AND ITS APPLICATIONS

Room-temperature liquid metal, such as eutectic gallium indium (EGaIn), has attracted significant attention for the fabrication of high-density electronics, functional composites, and two-dimensional nanomaterials due to the high electrical conductivity, high thermal conductivity, low toxicity, and its naturally formed oxide skin. Pulsed laser beams are proved to be promising to process liquid metal due to laser induced high temperature and high pressure. Although extraordinary progresses are made, limitations that remain in advanced manufacturing and material performance are crucial to overcome before liquid metal can be more practically used. The goal of this dissertation is to utilize the unique interaction between laser and liquid metal to design and fabricate nanomaterials with scalable functionalities towards potential device applications. 

This dissertation is composed of a general review of related background and experimental methods, followed by three chapters of detailed research and one chapter of conclusion. In the first research chapter, liquid metal is used, due to its high electrical conductivity and high fluidity, to create self-packaged, high-resolution liquid metal patterns by the advanced pulsed laser lithography (PLL) technology. The PLL method here, for the first time, can directly generate self-packaged liquid metal nano-patterns with high resolution without being limited by laser beam size. The electrically self-packaged material is an intriguing candidate to serve in demanding applications with high integration densities. In the second research chapter, liquid metal is utilized to boost the thermal conductivity of porous metal-organic frameworks (MOFs) to realize a high energy-harvesting efficiency. In this work, a facile and straightforward manufacturing method, laser shock-induced evaporation, is devised to deposit liquid metal nanoparticle (LMNP) thin layers to the surface of MOFs, resulting in the MOF@LMNP nanocomposites with a boosted thermal conductivity. In the last research chapter, liquid metal is employed to create large-scale metal oxide thin film patterns by an advanced confined laser transfer printing (CLTP) technique. This technology can generate metal oxide thin films patterns with tunable thickness and electrical property in nano-second scale that were previously inaccessible with conventional methods. This room temperature confined laser transfer printing method is promising to provide the possibility to pattern metal oxide thin films into advanced electronic components. As a summary, these studies present different laser manufacturing approaches in addressing liquid metal fabrication challenges from fundamental materials perspective.