Catalyst annealing and CNT growth were performed ina vertical cylinder atmospheric-pressure chamber built by theauthors. Flows of He (5 slm), C2H2(100 sccm), and H2(100 sccm)were maintained using electronic mass flow controllers (MFCs).After purging the tube with He for 10 min, the chamber was rampedup to 780◦C over 15 min (ramping rate: 50◦C/min), after whichgrowth of CNTs was carried out at 780◦C by adding acetylene gasto the flow for 5 min.