Excited Excitonic States in Single-Walled Carbon Nanotubes

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• 作者：Jacques Lefebvre ; Paul Finnie
• 刊名：Nano Letters
• 出版年：2008
• 出版时间：July 2008
• 年：2008
• 卷：8
• 期：7
• 页码：1890 - 1895
• 全文大小：767K
• 年卷期：v.8,no.7(July 2008)
• ISSN：1530-6992

文摘

Polarized photoluminescence excitation spectroscopy on individual SWNTs reveals not only the longitudinal and transverse E₁₁, E₂₂, and E₁₂ ground-state excitons but also excited excitonic states including the continuum. When heated, SWNTs are known to undergo a bandgap shift transition (BST), which effectively changes the nanotube dielectric environment. Here, we show that the entire spectrum of excitonic resonances blue shifts under this transition, with excited states showing larger shifts, approaching 100 meV for a 1 nm diameter nanotube. The excitonic binding energy, Coulomb self-energy correction, and dielectric shift under the BST are estimated. Analysis of this blue shift reveals the dominant effect of dielectric screening on SWNT excitonic states.