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. Carbon nanotubes were discovered in 1991 by Sumio Iijima at NEC Fundamental Research Laboratory in Japan while closely examining the soot produced by an arc discharge between graphite electrodes [1]. Since then, the progress made by researchers in understanding the physical properties of nanotubes has enhanced the potential for future applications of these unique structures. A carbon nanotube can be imagined as a graphene sheet (characterized by a single layer of carbon atoms arranged in a hexagonal lattice structure) rolled into a seamles