Electronic Transport in Novel Graphene Nanostructures
- Author(s): Gannett, William Joy
- Advisor(s): Zettl, Alex
- et al.
Graphene, a single sheet of sp2-bonded carbon atoms, is a two-dimensional material with an array of unique electronic, chemical, and mechanical properties. Applications including high performance transistors, chemical sensors, and composite materials have already been demonstrated. The introduction of chemical vapor deposition growth of monolayer graphene was an important step towards scalability of such devices. In addition to scalability, the exploration and application of these properties require the fabrication of high quality devices with low carrier scattering. They also require the development of unique geometries and materials combinations to exploit the highly tunable nature of graphene.
This dissertation presents the synthesis of materials, fabrication of devices, and measurement of those devices for three previously unexplored types of graphene devices. The first type of device is a field effect transistor made from chemical vapor deposited (CVD) graphene on hexagonal boron nitride (hBN) substrates. We demonstrate a significant improvement in carrier mobility from hBN substrates and are able to explore the sources of scattering in CVD graphene. The second type of device, fluorinated graphene transistors, allows us to examine doping and disorder effects from fluorination of the graphene crystal as well as electronic transport through unfluorinated folds in the graphene. With the third type of device we demonstrate a new route to graphene nanoribbon devices using both hBN flakes and BN nanotubes that may reduce disorder and allow precise measurements of quantum phenomena in graphene nanoribbons.