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Method for diameter and positioning control of CVD-grown carbon nanotubes using the precise placement of homogeneous metal nanoparticle catalysts

IP.com Disclosure Number: IPCOM000130417D
Publication Date: 2005-Oct-24
Document File: 4 page(s) / 410K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for diameter and positioning control of chemical vapor deposition (CVD) grown carbon nanotubes using the precise placement of homogeneous metal nanoparticle catalysts.

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Method for diameter and positioning control of CVD-grown carbon nanotubes using the precise placement of homogeneous metal nanoparticle catalysts

Disclosed is a method for diameter and positioning control of chemical vapor deposition (CVD) grown carbon nanotubes using the precise placement of homogeneous metal nanoparticle catalysts.

Background

              Diameter and positioning control are required for carbon nanotubes. For single-walled carbon nanotubes (CNTs), a correlation exists between the size of the catalyst particle and the diameter of the tube. However, no procedure enables the outer and inner diameter of multi-walled carbon nanotubes (MWCNTs) to be varied independently.

              Typically, large assemblies of catalyst particles are lithographically patterned on substrates from which CNTs grow. Procedures for the placement and aligned growth of large bundles of multi-walled carbon nanotubes do not exist.

General description

              The disclosed method is the CVD growth of carbon nanotube materials using the conversion of a carbon precursor at the surface of a metal nanoparticle catalyst of narrow size distribution. The result is the growth of carbon nanotubes with the required narrow diameter distribution. The location of the nanoparticle catalyst is directed through chemical and/or physical interactions with functional groups tethered to the surface in specific areas on the substrate.

              The key elements of the disclosed method include:

•             Rational synthesis of metal nanoparticle suspensions of narrow diameter distribution stabilized by moderately coordinating functional groups

•             Surface modification of substrates in designated locations with strongly coordinating functional groups for extracting metal nanoparticle catalysts from a suspension

•             CVD growth of carbon nanotube materials of a narrow diameter distribution from metal nanoparticle catalysts

Advantages

              The disclosed method provides advantages, including:
•             Improved functionality due to providing reproducible and optimal carbon nanotube devices with fine-tuned electronic properties
•             Improved functionality due to verifying the relationship between the diameter of the catalyst particle and that of the CNT

•             Improved functionality due to enabling the positioning of CNTs on a substrate by self-assembling individual catalyst particles on lithographically prepatterned and etched wafers

•             Improved functionality due to integrating CNT production with the conventional process flow

Detailed description

      The disclosed method is the surface growth of carbon nanotubes with diameter and positioning control. For example, the method produces multi-walled CNTs with inner diameters ranging from 5-10 nm, outer diameters ranging from 10-25 nm, and tubes up to 1 mm in length. Th tube interior can be filled with a variety of materials, such as compound semiconductors and metals.

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