Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Physics

Supervisor

Fanchini, Giovanni

Abstract

Since 2006, the experimental discovery of graphene, a single-layer of carbon atoms, has spurred tremendous efforts towards new graphene-based materials. In graphene research, there is a recent trend towards next-generation materials in which graphene layers are locally modified in a controlled fashion at the nanoscale and tailored for specific applications. Examples include nanoparticle-decorated graphene thin films with surface potential tailored for nanoelectronics or advanced catalysis, graphene nanoribbons, graphene quantum dots, and the scalable fabrication of tiny pores in graphene, which are suitable to applications requiring ultrathin molecular sieving membranes. This research is focused on the development of new applications of copper-nanoparticle (Cu-np) decorated graphene thin films, towards the metal-assisted etching of graphene and the synthesis of next-generation graphene-based materials. Two different methods were utilized for Cu-np deposition: thermal evaporation – a technique operating under thermodynamic equilibrium, and DC-biased radio-frequency sputtering – a plasma-based quasi-equilibrium technique. Both methods are capable of producing ultrathin Cu layers on graphene, which can be subsequently annealed to nucleate Cu-np’s of tuneable diameter depending on the Cu layer thickness. Both techniques are suitable to be used in conjunction with large-area graphene thin films prepared by solution processing. In this thesis, three examples are presented involving the use of Cu-np’s to process graphene. In the first example, both etching and synthesis are involved: It was found that the simultaneous removal of Cu-np’s and the underlying graphene has led to the formation of graphene ribbons from corrugated graphene layers, in which nanoparticles do not deposit on ridges and wrinkles. In a second example, it was demonstrated that Cu-np-assisted etching may lead to the formation of nanoporous graphene-based membranes that are finding interesting applications as water nanofilters for the removal of impurities (e.g. Fe3+ and Mn2+) from water. In a third example, plasma-assisted synthesis of carbon on Cu-np’s was shown to lead to the growth of curved graphene quantum dots, with resistive memory effects that can find applications in data storage. These examples well represent the versatility of the Cu-np assisted processing methodology of graphene thin films, towards a large variety of next-generation carbon-based nanomaterials.

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