Low Energy Electron Interactions with Precursor Molecules Relevant to Focused Electron Beam Induced Deposition

Copyrighted publications which are included in the printed version are linked though their DOI in the electronic version.In his 1959 speech “There is plenty of room at the bottom”, Richard Feynman shared his visions on how to manipulate matter on a small scale, down to individual atoms. Fifty years later, nanotechnology has become an essential tool in various disciplines, including advanced electronics, biotechnology and medicine. As a result, there exists an increasing demand for novel nano structures with tuneable physical and chemical properties. One viable way to meet this demand is through focused electron beam induced deposition (FEBID), which allows deposition of structures on the nanometer scale. Remarkable milestones have already been reached, yet there remain some challenges and goals to be met. For example, FEBID structures generally contain levels of impurities that adversely influence their properties. In addition, the theoretically possible sub-nanometer scale has still to be reached experimentally. These limitations are partially attributed to low energy electrons (< 50 eV) generated during the FEBID process, yet no systematic study on their mode of action in FEBID has been carried out. This Ph.D. project addresses the question of how low energy electrons may affect the purity and resolution in FEBID, with a special focus on dissociative electron attachment (DEA) and dissociative ionization (DI). It aims at laying down a stepping stone for understanding the underlying physics of the deposition process by identifying and characterizing the processes operative at a molecular level, unburdened by the high degree of complexity encountered in FEBID. More specifically, gas phase DEA and DI studies of the precursor molecules cobalt tricarbonyl nitrosyl, trimethyl (methylcyclopentadienyl) platinum (IV), palladium (II) and copper (II) hexafluoroacetylacetonate and titanium (IV) iso-propoxide were carried out. Fundamental insights gained from each study are presented in this thesis and are related to surface science studies where available. The research in this field is still in its infancy and it is hoped that this work can spark interest for extended investigations, eventually taking the FEBID technique beyond its current empirical approach.This project was funded through the University of Iceland Research Fun