Fabrication and characterization of nanofluidic TEM chip for laminar co-flow and cryofixation

Abstract

Transmission electron microscopy (TEM) technology is capable of observing and analyzing nano- and atomic-level materials using high spatial resolution. TEM has been used to study phenomena that could not be seen with conventional optical microscopes. Liquid-phase TEM technology has also gained much attention because it enables the observation and research of chemical reactions and biological structures. However, due to the characteristics of TEM, the thickness of a specimen needs to be within several hundreds of nanometers to provide a high mean-free-path in a vacuum. Thus, a sampling of liquid TEM imaging requires delicate and high-level techniques. Furthermore, liquid TEM chips with controllable nanofluid is an important issue and a significant challenge beyond the limitations of existing techniques. This thesis deals with the fabrication techniques of nanofluidic TEM chip and its demonstration of laminar co-flow formation and cryofixation. This thesis is composed of 5 chapters in total. In the first chapter, backgrounds and objectives are introduced and the second and third chapters introduce new materials and processes to fabricate nanofluidic chips and the experimental results from said nanofluidic chips. In the fourth section, we present the results of fluid connections, laminar co-flow formation, and cryofixation experiments using the nanofluidic chip. The final chapter deals with a new graphene transfer method for making nanofluidic chips with graphene windows which are robust and of high quality. The nanofluidic TEM chip, which is the result of this study, can reinforce the novel research in physics, chemistry, and biology. It can also be extended to the field of reaction dynamics and structural studies. Due to the advantages of platform technology, it can not only contribute to the basic sciences research, but it can also be applied to commercial products with various functions such as integrated electrodes and light sources.