Assembly and Alignment of High Packing Density Carbon Nanotube Arrays Using Lithographically Defined Microscopic Water Features

Abstract

High packing density aligned arrays of semiconducting carbon nanotubes (CNTs) are required for many electronics applications. Past work has shown that the accumulation of CNTs at a water−solvent interface can drive array self-assembly. Previously, the confining interface was a large-area, macroscopic feature. Here, we report on the CNT assembly on microscopic water features. Water microdroplets are formed on 10−100 μm wide hydrophilic stripes patterned on a substrate. Exposure to CNTs dispersed in solvent accumulates CNTs at the microdroplet−solvent interface, driving their alignment and deposition at the microdroplet− solvent−substrate contact line. Compared with macroscopic methods in which the contact line uncontrollably moves across the substrate as it is pulled out of the liquids, the hydrophilic patterns and microdroplets allow pinning of the contact line. As CNTs deposit, the contact line self-translates, allowing for dense CNT packing. We realize monolayer CNT arrays aligned within ±3.9°at density of 250 μm −1 and field effect transistors with a high current density of 1.9 mA μm −1 and transconductance of 1.2 mS μm −1 at −0.6 V drain bias and 60 nm channel length.

Stretchable and Flexible Painted Thermoelectric Generators on Japanese Paper Using Inks Dispersed with P- and N-Type Single-Walled Carbon Nanotubes

“…Therefore, the difference in dispersibility is believed to affect the thickness of the layer. The relationship between the bundle diameter and dispersibility of SWCNTs has been reported for different dopants [62,63]. In the p-type SWCNT layer, the ink was easily absorbed by the Japanese paper because of its very small bundle diameter compared with the fabric diameter of the paper, as shown in Figure 2c.…”