Bias-induced modulation of ultrafast carrier dynamics in metallic single-walled carbon nanotubes
| Autor: | Jun Takeda, Kazuhiro Yanagi, Keisuke Maekawa, Yasuo Minami, Ikufumi Katayama, Masahiro Kitajima |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
business.industry 02 engineering and technology Carbon nanotube 021001 nanoscience & nanotechnology 01 natural sciences law.invention Metal law Modulation visual_art 0103 physical sciences visual_art.visual_art_medium Optoelectronics 010306 general physics 0210 nano-technology business Carrier dynamics Ultrashort pulse |
| Zdroj: | Physical Review B. 97 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | The gate bias dependence of excited-state relaxation dynamics in metallic single-walled carbon nanotubes (MCNTs) was investigated using pump-probe transient absorption spectroscopy coupled with electrochemical doping through an ionic liquid. The transient transmittance decayed exponentially with the pump-probe delay time, whose value could be tuned via the Fermi-level modulation of Dirac electrons under a bias voltage. The obtained relaxation time was the shortest when the Fermi level was at the Dirac point of the MCNTs, and exhibited a U-shaped dependence on the bias voltage. Because optical dipole transitions between the Dirac bands are forbidden in MCNTs, the observed dynamics were attributed to carrier relaxation from the E11 band to the Dirac band. Using a model that considers the suppression of electron-electron scattering (impact ionization) due to Pauli blocking, we could qualitatively explain the obtained bias dependence of the relaxation time. |
| Databáze: | OpenAIRE |
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