Prolonged spontaneous emission and dephasing of localized excitons in air-bridged carbon nanotubes

Ibrahim Sarpkaya, Zhengyi Zhang, William Walden-Newman, Xuesi Wang, James Hone, Chee W. Wong, Stefan Strauf

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64 Scopus citations

Abstract

The bright exciton emission of carbon nanotubes is appealing for optoelectronic devices and fundamental studies of light-matter interaction in one-dimensional nanostructures. However, to date, the photophysics of excitons in carbon nanotubes is largely affected by extrinsic effects. Here we perform time-resolved photoluminescence measurements over 14 orders of magnitude for ultra-clean carbon nanotubes bridging an air gap over pillar posts. Our measurements demonstrate a new regime of intrinsic exciton photophysics with prolonged spontaneous emission times up to T 1 =18 ns, about two orders of magnitude better than prior measurements and in agreement with values hypothesized by theorists about a decade ago. Furthermore, we establish for the first time exciton decoherence times of individual nanotubes in the time domain and find fourfold prolonged values up to T 2 =2.1 ps compared with ensemble measurements. These first observations motivate new discussions about the magnitude of the intrinsic dephasing mechanism while the prolonged exciton dynamics is promising for applications.

Original languageEnglish
Article number2152
JournalNature Communications
Volume4
DOIs
StatePublished - 2013

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