Transition metal dichalcogenides and graphene: band structure investigation and molecular functionalization

Ultra-thin materials of only a few atoms thick are known as two-dimensional (2D) materials. In the past decade, these materials have transformed how scientists study and design new technologies. Unlike their thicker, bulk forms, these sheet-like materials have unusual properties that can be changed in surprising ways. Their behaviour can be tuned not only by altering their chemical makeup but also by applying pressure, stretching, or voltage. This makes them highly promising for creating future generations of ultra-small electronic devices and advanced light-based technologies. 

In her thesis, Giovanna Feraco explores many sides of 2D materials, from how they are made to how their properties can be controlled. She used several fabrication methods, including chemical growth techniques and carefully peeling off thin layers from crystals. To understand them in detail, Feraco examined their chemistry and how electrons move inside them, using powerful tools that can see atoms and track electrons. 

Key investigations within this thesis included how certain molecules can “heal” defects in a single-layer material called MoS₂, how twisting two layers of WS₂ affects their electronic structure, and how unusual flat bands appear in twisted bilayer graphene. 

Feraco also explored the chemical composition and electronic structure of a material made by adding molybdenum to WTe₂, looking at both its bulk and thin layer forms. Together, these findings deepen our understanding of how 2D materials work, opening doors to new ways of designing faster, smaller, and more efficient technologies.

Dissertation: https://hdl.handle.net/11370/5d5d2807-176f-4254-aee0-cc76ffac4df4