University of Cambridge > Talks.cam > Semiconductor Physics Group Seminars > Hyperspectral imaging of exciton dynamics in individual carbon nanotubes controlled by high magnetic fields

Hyperspectral imaging of exciton dynamics in individual carbon nanotubes controlled by high magnetic fields

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Semiconducting carbon nanotubes (CNTs) provide an exceptional platform for studying one dimensional excitons (bound electron-hole pairs), but the role of defects and quenching centres in controlling emission remains controversial. Here we show that by wrapping the CNT in a polymer sheath and cooling to 4.2 K, ultra-narrow photoluminescence (PL) emission linewidths below 80 micro-eV can be seen from individual solution processed CNTs. Hyperspectral imaging of the tubes identifies local emission sites and shows that previously dark quenching segments can be brightened by the application of high magnetic fields and their effect on exciton transport and dynamics can be controlled. 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.

This talk is part of the Semiconductor Physics Group Seminars series.

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