Optical Switching of Single-Wall Carbon Nanotube Absorption Through Field Gating

Semiconducting single-wall carbon nanotubes have an absorption band centered about approximately 0.7 eV. This arises from the transition between the first valence band Van Hove singularity and the first conduction band singularity in the density of states. These singularities lie close enough to the Fermi-level that it is possible to shift the Fermi-level sufficiently to exclude this electronic transition. In this experiment an attempt has been made to demonstrate the optical switching of this absorption band by applying a gating potential. The experiment is in progress and results are pending.