Abstract
Consisting of a single layer of carbon atoms packed in a honeycomb structure, graphene is highly promising as a low-dimensional material for next generation devices owing to its high carrier mobility, high crystal quality and economic price. In single layer graphene (SLG) and bilayer grapheme (BLG), charge carriers can be described as Dirac fermions to mimic relativistic particles owing to its unusual electronic structure. In this thesis, I have carried out the Angle-resolved photoemission spectroscopy (ARPES) to probe the electronic structure of materials. In case of BLG the energy splitting between the two valence π bands is proportional to the interaction between two layers. In our pervious study, the splitting energy of BLG on SiO2 is larger than graphite and epitaxial graphene due to a much weaker interaction between BLG and the SiO2 surface than between BLG and the SiC surface. To test the hypothesis whether stronger interlayer interaction implies smaller interlayer distance or not we have studied the electronic structure BLG on heavily n-doped Si substrate covered with 200 nm thick of SiO2 and compare with graphite on heavily n-doped Si substrate with native oxide. In graphite, a series of EDCs along the KH direction, we determined that the interlayer distance of graphite was about 3.35 Å. The presented result agrees with pervious literature result very well. In BLG/SiO2 system, the interlayer spacing is 3.12 Å. The larger energy splitting obtained from BLG/Si system and presented result reveals that a strong interlayer coupling existed on free standing BLG, results in a smaller interlayer spacing. The matrix element effect calculation was carried out to compare with the experimental result. After comparing to ARPES result, the reasonable interlayer spacing between 3.25 Å~ 3.20 Å obtained from simulation also agree with experimental conclusion.