- 0.025mm thick nickel foil, Alfa Aesar 12722
- 16 inch long, 13 mm ID, 15 mm OD, quartz tube
- 13 mm Septum stopper, Fisher FB57876
- Meker burner with multiple cones for a hotter, more uniform, temperature (575°C) than a Bunsen burner (350-400°C)
- Suction flas
- One-hole stopper
- Syringe needles, 18 G x 1.5 in, Fisher 148265D
Inquiry elements can be added to this laboratory experiment by allowing students to predict and test the effect of multiple CVD parameters on the graphene growth. The graphene synthesis consists of many elementary processes that occur throughout growth, including (1) adsorption of IPA onto the Ni surface, (2) decomposition of IPA on the Ni surface to form C atoms, (3) dissolution of C atoms into the Ni bulk, (4) supersaturation of the Ni bulk, (5) precipitation of C from the Ni bulk to the Ni surface, (6) diffusion of C on the Ni surface, (7) nucleation of graphene islands from the C on the surface, and (8) attachment of C to the existing graphene islands.6, 7, 11, 12 These processes are governed by basic chemistry concepts, such as adsorption, solubility, decomposition, precipitation, oxidation, reaction kinetics and thermodynamics, crystal nucleation and growth, phase diagrams, and vapor pressure, and can be manipulated by changing the CVD conditions to affect the graphene growth rate and coverage. For example, by considering reaction thermodynamics and kinetics, students can predict how changing the growth temperature, precursor flow rate, and precursor concentration will affect the reaction rate. We find that with increasing temperature, increasing flow rate, and increasing precursor composition, the reaction proceeds faster and, consequently, after a given reaction time, the graphene coverage on the Ni surface is higher.