Utilizing Cryogenic STEM for the Study of Low-Dimensional Functional Materials

Scanning Transmission Electron Microscopy (STEM) is a technique capable of characterizing a material's atomic and electronic structure with sub-angstrom resolution. It has been extensively used to study functional materials such as cathodes, solar cells, and catalysts, providing valuable insights into their properties. However, as STEM involves the use of many high-energy electrons, the samples can undergo electron beam-related damage. In this PhD defense, I will present atomic-scale studies of various functional materials, including 2D transition metal carbides and nitrides (MXenes) and a recently discovered 1D TiO2 compound. These materials are highly sensitive to electron beam exposure, but to study their pristine state, I cooled them in-situ to 96 K. I show that at low temperatures, the delicate bonding structure of these materials is preserved, and they undergo a variety of dynamic transformations not observed at room temperature (293 K).