Controllable Growth, Structure, and Low Field Emission of Well-Aligned CNx Nanotubes

Abstract

A large area and controllable synthesis of well-aligned CNx nanotubes with a high content of nitrogen (x⩽9%) was carried out by pyrolyzing metal phthalocyanine on an n-type Si(100) substrate. The diameters of the CNx nanotubes range widely from 20 to 200 nm, and the lengths range from 1 to 100 μm. The impressive bamboo-like CNx nanotubes consist of a few uniform, small, and well-ordered compartments. Investigation on morphology and elemental composition of the CNx nanotubes suggests that the overall tube morphology depends strongly on the nitrogen concentration. The higher the N content, the more compartmentalized of nanotubes become, which results in the formation of more curved CNx nanotubes. Our studies show that three different types of N atoms can be present in these materials. These are “pyridinic”, “pyrrolic”, and “graphitic” nitrogen with binding energies of 398.1, 401.0, and 405.1 eV, respectively. Field emission measurements suggest that the CNx nanotubes began to emit electrons at an electric f...