Dynamic optoelectric trapping and deposition of multiwalled carbon nanotubes.

Avanish Mishra,Steven T Wereley,Stuart J Williams,Katherine Clayton,Vanessa Velasco

doi:10.1038/micronano.2016.5

Avanish Mishra, Steven T Wereley + Show 3 more

Open Access

https://doi.org/10.1038/micronano.2016.5

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Abstract

In the path toward the realization of carbon nanotube (CNT)-driven electronics and sensors, the ability to precisely position CNTs at well-defined locations remains a significant roadblock. Highly complex CNT-based bottom–up structures can be synthesized if there is a method to accurately trap and place these nanotubes. In this study, we demonstrate that the rapid electrokinetic patterning (REP) technique can accomplish these tasks. By using laser-induced alternating current (AC) electrothermal flow and particle–electrode forces, REP can collect and maneuver a wide range of vertically aligned multiwalled CNTs (from a single nanotube to over 100 nanotubes) on an electrode surface. In addition, these trapped nanotubes can be electrophoretically deposited at any desired location onto the electrode surface. Apart from active control of the position of these deposited nanotubes, the number of CNTs in a REP trap can also be dynamically tuned by changing the AC frequency or by adjusting the concentration of the dispersed nanotubes. On the basis of a calculation of the stiffness of the REP trap, we found an upper limit of the manipulation speed, beyond which CNTs fall out of the REP trap. This peak manipulation speed is found to be dependent on the electrothermal flow velocity, which can be varied by changing the strength of the AC electric field.

Highlights

Owing to their extraordinary chemical, electrical and mechanical properties, carbon nanotubes (CNTs) have been widely explored as transistors, ion[1] and gas sensors[2,3], biosensors[4] and field emission devices[5,6]
Directgrowth chemical vapor deposition (CVD) methods produce a mixture of metallic and semiconducting CNTs and use high-temperature processes, which limit their applicability in microelectronic device fabrication[13]
We present a post-growth optoelectric method, referred to as rapid electrokinetic patterning (REP) that can trap both a single CNT and hundreds of vertically oriented CNTs by focusing a laser beam onto an electrode surface in the presence of a uniform alternating current (AC) electric field[28,29,30]

Summary

INTRODUCTION

Owing to their extraordinary chemical, electrical and mechanical properties, carbon nanotubes (CNTs) have been widely explored as transistors, ion[1] and gas sensors[2,3], biosensors[4] and field emission devices[5,6] We present a post-growth optoelectric method, referred to as rapid electrokinetic patterning (REP) that can trap both a single CNT and hundreds of vertically oriented CNTs by focusing a laser beam onto an electrode surface in the presence of a uniform alternating current (AC) electric field[28,29,30].

Apparatus

MATERIALS AND METHODS

RESULTS AND DISCUSSION