(Invited) Low Temperature Photoluminescence of Individual SWNTs Emitting at Telecommunication Wavelengths

In the quest for a nanoscale light emitter, carbon nanotubes have exceptional assets: they have a diameter dependent band-gap compatible with telecom wavelengths, they can possibly be operated at room temperature due to huge exciton binding energies and they emit anti-bunched photons, as required for quantum telecommunications. Here, we will present a complete set of low temperature photoluminescence (PL) experiments on single SWNTs emitting at the telecommunication wavelengths showing statistically relevant narrow line widths. These nanotubes are produced with a high temperature synthesis method (laser ablation – L-SWNTs), which is known to lead to a higher crystalline quality. The narrowing of the lines will be discussed in terms of a reduction of the exciton-phonon coupling in L-SWNTs. An exciton localization up to 6 times larger than in CVD-grown SWNTs is reported suggesting that the crystalline quality play a major role in the optical properties of nanotubes at low temperature. This study shows that several degrees of exciton localization are achievable in SWNTs. Therefore, identification of high crystalline quality nanotubes is a key step towards the control of exciton localization, going continuously from 0D to 1D confinement.