 Because of their unique 1-dimensional structure, carbon nanotubes posses many interesting electronic
properties and can be either metallic or semi-conducting depending on the way in which their
graphene sheet has been ‘rolled up’. The various nanotube types are denoted with the
nomenclature (n,m) which completely defines their geometry and electronic structure.
The semi-conducting tubes show strong band gap luminescence and by controlling the external environment
of the nanotubes we can study its effect on the luminescence of the semi-conducting nanotubes. The effects which have been studies so far
include the application of strong
magnetic fields, the effect of strain, temperature, pressure and the encapsulation of crystal structures
within the tubes. A detailed study of the vibrational modes of carbon nanotubes has also been carried out.
Fig : Typical photoluminescence excitation map for nanotubes at room temperature.
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