Effect of Metallic Substrate Type on the Growth of Multi-Walled Carbon Nanotubes During Chemical Vapor Deposition
Cady Cirbes, Vassar College ’16 and Alison Sagliocca, Vassar College ’16 and Prof. Stuart BelliWe studied the growth of multi-walled carbon nanotubes (CNT) on several surfaces to examine how the interactions of the substrate metal affected the structure and quantity of nanotubes that formed during chemical vapor deposition (CVD). Metallic nickel plates were successively plated with gold and then nickel to form the catalyst layer for CNT deposition. These plates were then heated in the CVD reactor as part of the deposition process, which also facilitates the atom migration between the metal layers. Increasing the current density while plating was found to increase the amount of nanotubes deposited on the plates. The deposition was characterized through Raman spectroscopy to examine the ratio of the nanotubes’ characteristic D and G bands. Other substrates, such as nickel-plated gold wires and nickel silicide covered silicon wafers were also used to compare and qualify the impact of substrate type on the CNTs formed. Nanotube and substrate behavior was also characterized using cyclic voltammetry to measure capacitance and current in potassium ferricyanide. The effect of the substrate was shown through the density of the nanotube growth, which affected the capacitance and size of the redox couple peaks observed. The nickel plates containing both nickel and gold plated layers resulted in nanotubes that performed the most ideally as electrodes.