Ajayan, Pulickel M.2019-05-172019-11-012019-052019-04-19May 2019Wang, Zixing. "Novel Synthesis and Modification Methods of 2-dimensional Materials." (2019) Diss., Rice University. <a href="https://hdl.handle.net/1911/106001">https://hdl.handle.net/1911/106001</a>.https://hdl.handle.net/1911/1060012-dimensional transition metal dichalcogenides (2D TMDCs) has gained increasing interest for their versatile and unique electrical, optical, chemical and mechanical properties, giving them wide applications in electrocatalysts, photocatalysts, energy storage, and optoelectronics. This thesis discusses three novel ways to synthesize and modify 2D TMDCs. The novel synthesis methods are based on chemical vapor deposition (CVD) and surfactant assisted colloidal wet synthesis. The modification method is based on chem-mechanical etching of the 2D monolayer TMDC materials on Si substrate. To be specific, 2-dimensional transition metal carbide (TMC), boride (TMB), and nitride (TMN) have been grown through two chemical vapor deposition methods. The 2D TMC, TMN and TMB grown using transition metal-copper immiscible system show superior mechanical hardness, scratch resistance, and oxidation resistivity. 2D MoxBy grown from molybdenum oxide power is larger in size and can be used to test various properties, including electrical conductivity and chemical catalytic activity. The preparation of 2D TMDC nanoribbons is through a reducing agent aqueous solution. This is a simple and tunable way for generating TMDC (MoS2 and MoSe2) nanoribbons from CVD grown 2D TMDCs on Si/SiO2. The reducing agents convert Mo(IV) from the defect sites to a lower oxidation state, thus disturbing the structure and expanding the defects. H2O acts as a detaching and tearing medium that pulls the TMDC flake into nanoribbons. The area of conversion, density, and thickness of the nanoribbons can be tuned by concentration and potency of the reducing agents. The 2D nanoribbons possess high structural integrity, zigzag edges with chalcogenide termination, and a consistent bandgap of 1.82 eV that is independent of ribbon width.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.TMDC2D materialschemical vapor depositionnanomaterialsThesis2019-05-17