Benzene, toluene, and xylene can be liquid precursors for graphene and carbon nanotube synthesis. However, the growth mechanisms can have greater variances for different carbon allotropes. In the case of graphene, Cu can be the catalyst for dehydrogenation and provides a weakly-coupled substrate for 2-dimensional graphene nucleation and growth. In the case of carbon nanotubes, Fe nanoparticles are essential to catalyze the C-C bonds breaking and dissolve carbon before the precipitation of a graphene cap over the catalyst particle where a tube forms. Controlling the precursor feed rate is crucial for a successful synthesis. In this research, we developed a low-pressure CVD system and a bubbler to control the feed rate of liquid precursors. The goal is to correlate the precursor molecules’ feed rate with the nucleation of graphene flakes to achieve a uniform layer of graphene at millimeter scale. Successful low temperature synthesis of graphene will open up enormous opportunities on device applications.
Hansen, Clayton, "Synthesis of Graphene by Liquid Precursors at Lower Temperatures" (2020). Physics Capstone Projects. Paper 83.