Continuous, floating evaporative assembly of aligned carbon nanotubes
AssigneeWisconsin Alumni Research Foundation
InventorsMichael Scott Arnold, Harold T. Evensen, Gerald Joseph Brady, Padma Gopalan, Yongho Joo
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Abstract
High density films of semiconducting single-walled carbon nanotubes having a high degree of nanotube alignment are provided. Also provided are methods of making the films and field effect transistors (FETs) that incorporate the films as conducting channel materials. The single-walled carbon nanotubes are deposited from a thin layer of organic solvent containing solubilized single-walled carbon nanotubes that is continuously supplied to the surface of an aqueous medium, inducing evaporative self-assembly upon contacting a solid substrate.
Claims17
A method of forming a film of aligned s-SWCNTs on a substrate, the method comprising:
- (a) partially submerging a hydrophobic substrate in an aqueous medium;
- (b) supplying a continuous flow of a liquid solution to the aqueous medium, the liquid solution comprising semiconductor-selective-polymer-wrapped s-SWCNTs dispersed in an organic solvent, whereby the liquid solution spreads into a layer on the aqueous medium at an air-liquid interface and semiconductor-selective-polymer-wrapped s-SWCNTs from the layer are deposited as a film of aligned semiconductor-selective-polymer-wrapped s-SWCNTs on the hydrophobic substrate, wherein the organic solvent in the layer, which is continuously evaporating, is continuously resupplied by the flow of the liquid solution during the formation of the film;
- and
- (c) withdrawing the hydrophobic substrate from the aqueous medium, such that the film of aligned semiconductor-selective-polymer-wrapped s-SWCNTs is grown along the length of the hydrophobic substrate as it is withdrawn from the aqueous medium.
A film comprising aligned s-SWCNTs, wherein the s-SWCNTs in the film have a degree of alignment of about ±20° or better and the single-walled carbon nanotube linear packing density in the film is at least 40 single-walled carbon nanotubes/μm.
A field effect transistor comprising:
- a source electrode;
- a drain electrode;
- a gate electrode;
- a conducting channel in electrical contact with the source electrode and the drain electrode, the conducting channel comprising a film comprising aligned s-SWCNTs, wherein the s-SWCNTs in the film have a degree of alignment of about ±15° or better and the single-walled carbon nanotube linear packing density in the film is at least 40 single-walled carbon nanotubes/μm;
- and
- a gate dielectric disposed between the gate electrode and the conducting channel.
Dependencies are inferred from the claim text.