UC Riverside

Carbon-based nano-materials, including single-walled carbon nanotubes (SWNTs), graphite nanoplatelets and graphene, possess remarkable electronic, optoelectronic properties, due to their unique dimensional and geometric structure. SWNT and graphene have recently emerged as a potential basis for new generation of electronic and optoelectronic devices.

In Chapter 1, the fundamental knowledge of graphene, SWNT and SWNT thin film are introduced, including their structure and physical properties, as well as fabrication, properties and applications. In chapter 2 and chapter 3, two examples of optoelectronic applications in SWNT thin films are discussed: 1. solid state SWNT thin film field effect transistor (FET) electro-optical modulator in which the gate potential induced electro-optical modulation is significantly enhanced by utilizing optimized transparent bottom gate device, large diameter SWNTs, and by increasing the ratio of semiconducting to metal SWNTs. 2. Ionic liquid based SWNT thin film modulator in which a very strong electro-optical modulation can be achieved in ionic liquid coated semiconducting SWNT thin film as a result of the position dependent shift of the SWNT Fermi level. The experimental results indicate that low conductivity semiconducting SWNT film is fascinating material and have wide range of optoelectronic applications. In chapter 4, effects of metal deposition on the conductivity of SWNT networks are discussed. It is found that controlled exposure of SWNT thin films to the e-beam evaporation of Cr leads to the formation of bis-hexahapto complexes at the SWNT sidewalls, thereby bridging adjacent carbon nanotubes and reducing the inter-nanotube junction resistance. In chapter 5, an example of optoelectronic applications in graphene is discussed. Controlled electro-oxidization modifies the electronic and optoelectronic properties of multilayer epitaxial graphene, and electro-chemical oxidized graphene has potential for UV detection applications.