Electric-Field Induced Activation of Dark Excitonic States in Carbon Nanotubes

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• 作者：T. Uda ; M. Yoshida ; A. Ishii ; Y. K. Kato
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：16
• 期：4
• 页码：2278-2282
• 全文大小：366K
• 年卷期：0
• ISSN：1530-6992

文摘

Electrical activation of optical transitions to parity-forbidden dark excitonic states in individual carbon nanotubes is reported. We examine electric-field effects on various excitonic states by simultaneously measuring photocurrent and photoluminescence. As the applied field increases, we observe an emergence of new absorption peaks in the excitation spectra. From the diameter dependence of the energy separation between the new peaks and the ground state of E₁₁ excitons, we attribute the peaks to the dark excited states which became optically active due to the applied field. Field-induced exciton dissociation can explain the photocurrent threshold field, and the edge of the E₁₁ continuum states has been identified by extrapolating to zero threshold.