Growth of well-aligned carbon nanotubes on a large area of Co–Ni co-deposited silicon oxide substrate by thermal chemical vapor deposition

We have grown vertically well-aligned multiwalled carbon nanotubes (CNT) on a large area of cobalt–nickel (Co–Ni) co-deposited silicon oxide substrate by thermal chemical vapor deposition using C2H2 gas, at 950°C. The diameter of CNTs is in the range of 50–120 nm and the length is about 130 μm. The grown CNTs have a bamboo structure and closed tip with no catalytic particles inside. As the particle size of Co–Ni catalyst decreases, the vertical alignment is enhanced. The CNTs exhibits a low turn-on voltage of 0.8 V/μm with an emission current density of 0.1 μA cm−2.