Towards a More Precise and Diverse Control on the Growth and Manipulation of Two Dimensional Materials(3/3)

Within the scope of this proposal, we plan to develop more precise ways to grow and manipulate the two dimensional materials of interest and study the underlying physics. First we plan to grow large grain twisted bilayer-graphene through manipulating the concentration gradient of carbon sources in the bulk catalyst. The ultimate goal is to precisely control the twist angle of the bilayer-graphene and understand the mechanism behind the generation of non-equilibrium twist angle. Second we plan to build a new generation low damage magnetron plasma enhanced chemical vapor deposition system to enable fast, lower temperature, and defect free graphene growth, and study the nucleation and growth dynamics. Third we will implement an inductive coupled plasma coil to effectively ionize the ammonia borane source in the growth process of hexagonal boron nitride. Fourth we will continue to grow multi-layered transition metal dichalcogenide film on metal film deposited semiconductor substrates through ion implantation of selenium or sulfur ions. The above study will advance our understanding in the role of defects in precise growth of 2D materials and contribute t the mass production of 2D materials in industrial applications.After the growth of the 2D materials, we will use scanning probe lithography or two photon oxidation/forging techniques to create local defects, use ion implantation to create uniform structural or doping defects, use plasma treatment to modify or dope the surface of the 2D materials.We will characterize the structure, excitonic dynamics, chemical bonding, and surface morphology of the treated 2D materials. In order to achieve the above goals, we will purchase and implement a new confocal micro-Raman/PL system, upgrade the existing AFM system to implement the Kelvin probe force microscopy capability.