To test the generality of non-isothermal growth, a limited set of in situ growth experiments were performed on catalyst films with a different thickness (1 nm) and composition (Fe). These experiments revealed similar results to those presented in Figures and, i.e. the Raman intensity from the CNTs in the non-isothermal growth experiments were significantly higher than isothermal growth (Figure ). Moreover, similar to the case of Co, we saw that the yield from Fe is maximized for a given cooling rate and temperature difference (Figure ), although the Δtc and ΔT are different compared to Co. The average Δtc was longer (~ 100 s) and the ΔT was shorter (~100 ºC) for Fe compared to Co. The observed differences between the two metal catalysts could be attributed to metal film dewetting kinetics, including reduction and particle formation; this is discussed later. Table shows a summary of the findings obtained from isothermal and non-isothermal ARES growth experiments, for 0.3nm Co and 1 nm Fe catalyst films.