  Electroluminescence from individual carbon nanotubes within split-gate
devices is investigated. By characterizing the air-suspended nanotubes with
photoluminescence spectroscopy, chirality is identified and electroluminescence
peaks are assigned. We observe electroluminescence linewidth comparable to
photoluminescence, indicating negligible heating and state-mixing effects.
Split-gate and bias voltage dependences are consistent with emission from an
electrostatically formed $pn$-junction.
