Carbon nanotube samples prepared by an electric-field-assisted assembly method appropriate for the fabrication processes of tip-based nanodevices

Abstract

In this paper, new techniques for fabricating carbon nanotube (CNT) samples appropriate for manufacturing tip-based CNT devices with a nanomanipulator system are presented. The CNT samples were made via an electric-field-assisted assembly method. To increase the electric field and for the simple alignment of two electrodes, a new design of an asymmetric electrode pair consisting of a knife-edged electrode and a flat electrode is proposed. The sharp edge of the electrode is designed to form a high electric field. It is appropriate for reducing the gap size, as its conductive layer is much narrower than that of the flat electrode. The electric-field-assisted assembly process of the CNTs was analyzed based on electrokinetics and experiments. Through experiments, a frequency range of 1–5 MHz was determined to be optimal for the CNT samples. The fabricated CNT samples displayed many CNTs protruded from the edge of the electrode. The average protrusion length was approximately 400 nm, and over 60% of the protruding CNTs were aligned parallel within an angle of 30°. A single CNT on a sample can be detached by a nanomanipulator system, which is useful for the efficient development of various types of tip-based nanodevices.