Theory of field and thermionic electron emissions of carbon nanotubes

Carbon nanotubes (CN) exhibit not only experimentally excellent field-emission features, low threshold field, high current density and thermal stability, but also the current-voltage (I-V) characteristic deviates from the Fowler-Nordheim (FN) type behavior at high current density, which induces theoretical interesting to understand new physics in CN field emission. In principle, the energy band structure should play an important role in the field emission for low-dimensional materials. Based on the low-energy band structure of CNs we develop a generalized FN theory of field emission of CNs, giving analytically different I-V characteristics and thermionic emission equation, which provide a physical understanding of novel phenomena in CN field and thermionic emissions.