Simple route to large-scale ordered arrays of liquid-deposited carbon nanotubes

Carbon nanotube (CNT) transistors, sensors, and field emitters have recently attracted much attention. However, it is difficult to form ordered submonolayer arrays of these molecular wires because of their high aspect ratio and strong inter-nanotube van der Waals interactions. A tractable procedure for the formation of horizontally aligned CNT arrays will assist in incorporating them into devices that can be mass produced. Such a method is described here. Large-scale, ordered arrays of CNTs were deposited at room temperature from aqueous suspensions onto silanized SiO2 surfaces. When these arrays were used as the source-drain channel for field-effect transistors, device performance showed a strong dependence on CNT orientation.