Fabrication and properties of nanocapacitors and nanostructures prepared by nanosphere lithography

Publication Type:
Thesis
Issue Date:
2016
Full metadata record
Nanosphere lithography was used to synthesise nanoscale capacitors as well as arrays of zinc oxide nanostructures. Close-packed polystyrene nanospheres were used as masks and periodic arrays of metals / metal oxides were deposited through the inter-sphere voids onto substrates. The technique was optimised to produce hexagonally close-packed arrays of polystyrene spheres for a range of sphere sizes (200-1500 nm). Nanoscale capacitors were synthesised via evaporative and sputter deposition to produce structures consisting of gold / metal oxide / gold layers on a silicon substrate. A range of metal oxides were investigated including alumina, silica, zinc oxide, titania and hafnia. A significant development reported here involves the charging of these devices and their characterisation using scanning electron microscopy techniques. These methods enable the measurement of the charging time constants of materials in a non-destructive fashion without the requirement to connect wires or contacts. Nanostructures fabricated using zinc oxide as a dielectric material produced rings of zinc oxide nanostructures on the silicon substrate and a mechanism for the ring formation is proposed here. The resultant structures were used as templates to seed the hydrothermal growth of zinc oxide nanostructures. Arrays of zinc oxide nanostructures were also produced using techniques that enable control over the position and amount of growth.
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