Self-assembled monolayers on metal oxides : applications in nanotechnology

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The thesis describes the use of phosph(on)ate-based self-assembled monolayers (SAMs) to modify and pattern metal oxides. Metal oxides have interesting electronic and magnetic properties such as insulating, semiconducting, metallic, ferromagnetic etc. and SAMs can tailor the surface properties. FePt nanoparticles (NPs) are promising candidates for magnetic data storage applications due to their superior properties. In this thesis, the use of SAMs on conducting metal oxides for electrical applications and at the adsorption of magnetic NPs for data storage applications have been studied. By combining patterning techniques and self-assembly, functional inorganic-organic composite structures have been created. Chapter 1 provides a general introduction to this thesis. In Chapter 2, a literature overview of SAMs on metal oxides is given. In Chapter 3, the assembly of phosph(on)ate-based SAMs with CH3, NH2, SH, COOH end groups on single crystalline-aluminum oxide (Al2O3) substrates is described. In Chapter 4, the electrochemical properties of SAMs on conducting metal oxide Nb-STO are addressed. Chapter 5 describes the low kinetic energy deposition of Pt top contacts on alkylphosphate SAMs by pulsed laser deposition (PLD) and electrical characterization of these SAMs on a conducting Nb-STO metal oxide susbtrate. Chapter 6 describes the controlled assembly of FePt NPs on phosph(on)ate-based SAM-modified Al2O3 substrates. Chapter 7 presents the preparation of high-resolution FePtAu NP patterns on an Al2O3 surface prepared by nanoimprint lithography (NIL) and nanomolding in capillaries (NAMIC). The results described in this thesis show the versatility and efficiency of the use of phosph(on)ate-based SAMs to modify metal oxide surfaces. The use of SAMs on conducting metal metal oxides opens new possibilities for electrochemical studies. Metal top contact fabrication without causing shorts between the SAM and the substrate, combined with the insulating efficiency of the SAM, is promising for electrical device fabrication as well as for fundamental studies to understand the electrical properties of organic monolayers. Combining patterning techniques with chemical modification achieved by SAMs for controlled assembly and patterning magnetic nanoparticles on metal oxides can be used to prepare spintronic devices.