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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Microscopic and spectroscopic studies of growth and electronic structure of epitaxial graphene

Sharma, Nikhil 06 April 2009 (has links)
It is generally believed that the Si technology is going to hit a road block soon. Amongst all the potential candidates, graphene shows the most promise as replacement material for the aging Si technology. This has caused a tremendous stir in the scientific community. This excitement stems from the fact that graphene exhibits unique electronic properties. Physically, it is a two-dimensional network of sp₂bonded carbon atoms. The unique symmetry of two equivalent sublattices gives rise to a linear energy dispersion for the charge carriers. As a consequence, the charge carriers behave like massless Dirac particles with a constant speed of c/300, where c is the speed of light. The sublattice symmetry gives rise to unique half-integer quantum hall effect, Klein's paradox, and weak antilocalization. In this research work, I was able to successfully study the growth and electronic structure of EG on SiC(0001), in ultra-high vacuum and low-vacuum furnace environment. I used STM to study the growth at an atomic scale and macroscopic scale. With STM imaging, I studied the distinct properties of commonly observed interface region (layer 0), first graphene layer, and the second graphene layer. I was able to clearly resolve graphene lattice in both layer 1 and 2. High resolution imaging of the defects showed a unique scattering pattern. Raman spectroscopy measurements were done to resolve the layer dependent signatures of EG. The characteristic Raman 2D peak was found to be suppressed in layer 1, and a single Lorentzian was seen in layer 2. Ni metal islands were grown on EG by e-beam deposition. STM/ STS measurements were done to study the changes in doping and the electronic structure of EG with distance from the metal islands.

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