Laser-induced nanoscale thermocapillary flow for purification of aligned arrays of single-walled carbon nanotubes.
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abstract
Although aligned arrays of single-walled carbon nanotubes (SWNTs) have outstanding potential for use in broad classes of advanced semiconductor devices, the relatively large population of metallic SWNTs (m-SWNTs) that results from conventional growth techniques leads to significantly degraded performance. Recently reported methods based on thermocapillary effects that enable removal of m-SWNTs from such arrays offer exceptional levels of efficiency, but the procedures are cumbersome and require multiple processing steps. Here we present a simple, robust alternative that yields pristine arrays of purely semiconducting SWNTs (s-SWNTs) by use of irradiation with an infrared laser. Selective absorption by m-SWNTs coated with a thin organic film initiates nanoscale thermocapillary flows that lead to exposure only of the m-SWNTs. Reactive ion etching eliminates the m-SWNTs without damaging the s-SWNTs; removal of the film completes the purification. Systematic experimental studies and computational modeling of the thermal physics illuminates the essential aspects of this process. Demonstrations include use of arrays of s-SWNTs formed in this manner as semiconducting channel materials in statistically relevant numbers of transistors to achieve both high mobilities (>900 cm2 V(-1) s(-1)) and switching ratios (>10(4)). Statistical analysis indicates that the arrays contain at least 99.8% s-SWNTs and likely significantly higher.
Du, F., Felts, J. R., Xie, X. u., Song, J., Li, Y., Rosenberger, M. R., ... Rogers, J. A.
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35
complete list of authors
Du, Frank||Felts, Jonathan R||Xie, Xu||Song, Jizhou||Li, Yuhang||Rosenberger, Matthew R||Islam, Ahmad E||Jin, Sun Hun||Dunham, Simon N||Zhang, Chenxi||Wilson, William L||Huang, Yonggang||King, William P||Rogers, John A
