Carbon Nanotube Thin Films as Flexible Substrates for the Support of Inorganic Nanostructures

Abstract

<p>Carbon nanotubes (CNTs) are arguably the most widely studied material within the field of nanotechnology. The impressive physical and electronic properties of these materials have led to their investigation in a diverse range of applications. In recent years, the deposition of inorganic nanoparticles upon the surface of CNTs has received much attention. Research within this field has been driven by the desire to develop new composite materials exhibiting novel electronic, optical, and catalytic properties. In addition to the decoration of individual nanotubes, several groups have also investigated the use of CNT thin films as scaffolds for the assembly of inorganic nanostructures as well as other secondary components, including polymers and biomaterials. Nanotube films exhibit a number of physical properties that make them suitable for such applications, displaying impressive electrical conductivity, flexibility, and thermal stability while also possessing a high surface area upon which chemical modification can be conducted.</p><p>This thesis presents work that demonstrates the potential of CNT thin films as flexible conductive scaffolds for the support of a variety of inorganic nanostructures. Procedures are described for the preparation of SWNT -Au nanoparticle composite films that, as subsequently demonstrated, are suitable substrates for the growth of III-V semiconductor nanowires using gas-source molecular beam epitaxy. At the time of writing, the majority of published research within this field focused upon the preparation of SWNT composite films containing spherical metallic or semiconductor nanoparticles. In contrast, the growth of semiconductor nanowires upon nanotube thin films had not been explored. The work described in this thesis therefore represents the development of a novel composite material that combines the flexibility of CNT films with the unique optoeletronic properties exhibited by semiconductor nanowires. The development of functional electronic devices incorporating these materials is also discussed, as is the extension of the methods developed to investigate novel composite materials that combine other inorganic nanostructures with carbon based substrates.</p>