Fabrication and Physical Properties of Novel Two-dimensional Crystal Materials Beyond Graphene: Germanene Hafnene and PtSe2

This thesis reports on essential experimental work in the field of novel two-dimensional (2D) atomic crystals beyond graphene. It especially describes three new 2D crystal materials namely germanene hafnene and monolayer PtSe2 fabricated experimentally for the first time using an ultra-high vacuum molecular beam epitaxy (UHV-MBE) system.Multiple characterization techniques including scanning tunneling microscope (STM) low energy electron diffraction (LEED) scanning transmission electron microscope (STEM) and angle-resolved photoemission spectroscopy (ARPES) combined with theoretical studies reveal the materials’ atomic and electronic structures which allows the author to further investigate their physical properties and potential applications. In addition a new epitaxial growth method for transition metal dichalcogenides involving direct selenization of metal supports is developed. These studies represent a significant step forward in expanding the family of2D crystal materials and exploring their application potentials in future nanotechnology and related areas.