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An Optoelectronic Device for Carbon Nanotube Manipulation and Separation

IP.com Disclosure Number: IPCOM000132314D
Publication Date: 2005-Dec-07
Document File: 3 page(s) / 141K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that creates virtual electrodes for creating non-uniform AC electric fields in a fluidic system to trap or repel small objects, including carbon nanotubes (CNT), through dielectrophoretic (DEP) forces. Optoelectronic tweezers (OET) manipulate and separate single-walled carbon nanotubes (SWNTs), according to their electronic and dielectric properties. Benefits include a simple, reliable, and inexpensive way to manipulate and separate CNT.

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An Optoelectronic Device for Carbon Nanotube Manipulation and Separation

Disclosed is a method that creates virtual electrodes for creating non-uniform AC electric fields in a fluidic system to trap or repel small objects, including carbon nanotubes (CNT), through dielectrophoretic (DEP) forces. Optoelectronic tweezers (OET) manipulate and separate single-walled carbon nanotubes (SWNTs), according to their electronic and dielectric properties. Benefits include a simple, reliable, and inexpensive way to manipulate and separate CNT.

Background

The separation and manipulation of CNT is of great importance for electronic applications. Currently, the growth of CNT produces a mixture of both metallic and semi conducting CNT. For transistor applications, it is desired to have 100% semi conducting tubes and for interconnect applications, 100% metallic tubes. Developing a process to efficiently and effectively separate metallic from semiconducting CNT is of great technological importance.

General Description

The disclosed method creates virtual electrodes for creating non-uniform AC electric fields in a fluidic system to trap or repel small objects, including CNT through DEP forces. The disclosed method uses OET to manipulate and separate SWNTs, according to their electronic and dielectric properties. The DEP force is generated by the interaction between the applied electric field and the induced electric dipoles in neutral particles.

To achieve a light-induced DEP, a prior-art device structure is used (see Figure 1). The 1μm thick amorphous silicon is coated with a 20nm silicon nitride layer to prevent electrolysis. The amorphous silicon layer has high resistance in the dark, resulting in a small voltage drop across the liquid layer. Under the light, the illuminated area of the photoconductive layer becomes conductive and works as a virtual electrode. The virtual electrodes create a non-uniform electric field in the liquid layer, producing a DEP force on the p...