Effect of a square wave on an assembly of multi-walled carbon nanotubes using AC dielectrophoresis

Here, we report an alignment and attachment of multi-walled carbon nanotubes (MWNTs) between microelectrodes using alternating current (AC) dielectrophoresis, where the AC dielectrophoresis is induced by a square wave rather than the conventional sinusoidal wave. A parametric study showed that square-wave-based AC dielectrophoresis is useful in alignment and attachment of MWNTs on a microelectrode gap, and that the square wave is effective in aligning the MWNTs in a low-frequency range (∼10 kHz) without addition of a direct current (DC) signal. Moreover, we could attach the MWNTs between microelectrodes with minimal amounts of impurities by adjusting the square-wave duty cycle.