# US 8,784,673 B2 · Highly organized single-walled carbon nanotube networks and method of making using template guided fluidic assembly

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- Number: US 8,784,673 B2
- Document ID: US8784673B2
- Status: Granted
- Kind: B2
- Application number: 12/619,187
- Filed: 2009-11-16
- Published: 2010-07-22
- Granted: 2014-07-22
- Earliest claimed: 2008-11-14
- Assignees: Northeastern University
- Applicants: Xugang Xiong; Laila Jaberansari; Ahmed Busnaina; Yung Joon Jung; Sivasubramanian Somu; Moneesh Upmanyu
- Inventors: Xugang Xiong; Laila Jaberansari; Ahmed Busnaina; Yung Joon Jung; Sivasubramanian Somu; Moneesh Upmanyu
- Web page: https://patentgrep.com/patent/US8784673B2

## CPC

- H10K 71/191: {characterised by provisions for the orientation or alignment of the layer to be deposited}
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- H01B 1/04: mainly consisting of carbon-silicon compounds, carbon or silicon
- H01B 1/24: the conductive material comprising carbon-silicon compounds, carbon or silicon
- H10K 85/221: {Carbon nanotubes}
- Y10T 428/24479: including variation in thickness
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Methods for fabricating templates for nanoelement assembly and methods for fluid-guided assembly of nanoelements are provided. Templates are fabricated by plasma modification of surface hydrophilicity and production of a network of hydrophobic trenches having a hydrophilic bottom surface. Single-walled carbon nanotubes (SWNT) can be assembled into stable films, ribbons, and wires of nanoscale thickness and nanoscale or microscale width and length. The nanofilm assemblies prepared according to the invention are highly conductive and can be used in the fabrication of a wide variety of microscale and nanoscale electronic devices.

## Claims

### Claim 1

A method for fabricating a nanofilm, comprising the steps of:
providing a template for fabricating a nanofilm, the template comprising a substrate comprising an upper hydrophobic surface and one or more nanoscale trenches, the trenches comprising hydrophobic sidewalls below the upper hydrophobic surface and a bottom plasma-etched, to provide roughened hydrophilic surface;
submersing the template or a portion thereof in a suspension of single-walled carbon nanotubes (SWNT) in a polar solvent; and
pulling the submersed template or portion thereof up through an air-water interface of the suspension, whereby SWNT from the suspension become aligned in the trenches to form a nanofilm within the trenches.

### Claim 2 (depends on 1)

The method of claim 1, wherein the bottom hydrophilic surface possesses a hydrophilicity corresponding to a contact angle of less than 5 degrees.

### Claim 3 (depends on 1)

The method of claim 1, wherein the hydrophobic surface possesses a hydrophobicity corresponding to a contact angle of greater than 45 degrees.

### Claim 4 (depends on 1)

The method of claim 1, wherein the hydrophobic surface is formed by a layer of hydrophobic mask material deposited on the substrate.

### Claim 5 (depends on 4)

The method of claim 4, wherein portions of the hydrophobic mask material are removed to form the one or more nanoscale trenches, exposing the underlying substrate as the bottom hydrophilic surface of the trenches.

### Claim 6 (depends on 5)

The method of claim 5 further comprising, after the formation of one or more nanofilms, the step of removing the hydrophobic mask material from the substrate.

### Claim 7 (depends on 4)

The method of claim 4, wherein the hydrophobic material is polymethyl methacrylate.

### Claim 8 (depends on 1)

The method of claim 1, wherein the suspension comprises a mixture of semiconducting and metallic SWNT.

### Claim 9 (depends on 1)

The method of claim 1, wherein the nanoscale trenches have a width of at least 50 nm.

### Claim 10 (depends on 9)

The method of claim 9, wherein the nanoscale trenches have a width in the range of 50 nm to 1000 nm.

### Claim 11 (depends on 1)

The method of claim 1, wherein the nanoscale trenches have a depth in the range of 50 nm to 500 nm.

### Claim 12 (depends on 1)

The method of claim 1, wherein the nanoscale trenches have an aspect ratio of about 50 nm depth to about 150 nm width.

### Claim 13 (depends on 1)

The method of claim 1, wherein the formed nanofilms have an essentially linear current-voltage relation.

### Claim 14 (depends on 1)

The method of claim 1, wherein the formed nanofilms have a non-linear current-voltage relation.

### Claim 15 (depends on 1)

The method of claim 1, wherein the substrate comprises a material selected from the group consisting of silicon, silicon oxide, gold, and a hydrophobic polymer.