Joule heating induced negative differential resistance in freestanding metallic carbon nanotubes

The features of the IV characteristics of metallic carbon nanotubes (m-CNTs) in different experimental setups are studied using semiclassical Boltzmann transport equation together with the heat dissipation equation to account for significant thermal effects at high electric bias. The model predicts that the shape of the m-CNT characteristics is basically controlled by heat removal mechanisms. In particular, the authors show that the onset of negative differential resistance in freestanding nanotubes finds its origins in strong transport nonlinearities associated with poor heat removal unlike in substrate-supported nanotubes.