Length Dependence of Ultrafast Optical Nonlinearities in Vertically Aligned Multiwalled Carbon Nanotube Films

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• 作者：Hendry Izaac Elim ; Yanwu Zhu ; Chorng-Haur Sow
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：August 11, 2016
• 年：2016
• 卷：120
• 期：31
• 页码：17733-17738
• 全文大小：467K
• 年卷期：0
• ISSN：1932-7455

文摘

Tube-length-dependent optical nonlinearities of vertically aligned multiwalled carbon nanotube (MWNT) films have been investigated by Z-scan and transient absorption measurements with femtosecond laser pulses in the near-IR spectral range from 780 to 1550 nm. Both saturable absorption and optical Kerr nonlinearity are found to be dependent on excitation wavelength and tube length, indicating that band-filling in semiconducting tubes and longitudinal surface plasmon resonance in metallic tubes play an important role, respectively. The 1 ps relaxation time for the nonlinear response of the MWNT films, however, is independent of tube length, as evidenced from dissipation of excited energy in the radial direction. Such ultrafast vertically length-dependent in CNT can significantly contribute to fabricate vertically nanochips in various types of integrated nanodevices just like a creation of a living three-dimensional fish bone (a kind of cowfish).