Electroluminescence and thermal radiation from metallic armchair carbon nanotubes with defects

Bias-induced light emission and thermal radiation from conducting channels of metallic armchair carbon nanotubes (CNTs) with defects are studied theoretically within the framework of nonequilibrium Green's function method based on a tight-binding model. Localized states induced by the single vacancy defect and single Stone-Wales defect in the low-energy range enhance electroluminescence significantly while they reduce thermal radiation under zero bias. The influence of the diameters of the CNTs with defects on the radiation is discussed. Radiations from metallic CNTs in thermal equilibrium show black-body-like spectrum. For perfect nanotubes with small diameter, their thermal radiations are nearly independent on the tube diameter due to the confinement of the thermal excitations in the tube's circular direction. Our study is important for optoelectronic applications of CNTs with defects.