Precise control of multiwall carbon nanotube diameters using thermal chemical vapor deposition

We grow multiwall carbon nanotube (CNT) films using thermal chemical vapor deposition at atmospheric pressure using a mixture of acetylene and nitrogen from a 4-nm-thick Ni film catalyst. CNTs are characterized using electron microscopy and Rutherford backscattering spectrometry. CNTs grown with this method are extremely uniform in diameter, both throughout the sample and within the lengths of individual tubes. Nanotube outer diameters, ranging from 5–350 nm, and the total deposition of carbon material, increase exponentially with growth temperature from 630 °C–790 °C.