title: Hyperspectral imaging of exciton photoluminescence in individual carbon nanotubes controlled by high magnetic fields.
abstract: Semiconducting carbon nanotubes (CNTs) provide an exceptional platform for studying one-dimensional excitons (bound electron-hole pairs), but the role of defects and quenching centers in controlling emission remains controversial. Here we show that, by wrapping the CNT in a polymer sheath and cooling to 4.2 K, ultranarrow photoluminescence (PL) emission line widths below 80 μeV can be seen from individual solution processed CNTs. Hyperspectral imaging of the tubes identifies local emission sites and shows that some previously dark quenching segments can be brightened by the application of high magnetic fields, and their effect on exciton transport and dynamics can be studied. Using focused high intensity laser irradiation, we introduce a single defect into an individual nanotube which reduces its quantum efficiency by the creation of a shallow bound exciton state with enhanced electron-hole exchange interaction. The emission intensity of the nanotube is then reactivated by the application of the high magnetic field.
authors.affiliation: Department of Physics, Clarendon Laboratory , Parks Road, Oxford, OX1 3PU, United Kingdom.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Alexander-Webber
authors.forename: Clement
authors.initials: C
authors.lastname: Faugeras
authors.forename: Piotr
authors.initials: P
authors.lastname: Kossacki
authors.forename: Marek
authors.initials: M
authors.lastname: Potemski
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Hee Dae
authors.initials: HD
authors.lastname: Kim
authors.forename: Samuel D
authors.initials: SD
authors.lastname: Stranks
authors.forename: Robert A
authors.initials: RA
authors.lastname: Taylor
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Nicholas
keywords: Aharonov−Bohm effect; Carbon nanotube; PFO; exciton