High performance field effect transistors comprising carbon nanotubes fabricated using solution based processing

• US 7,226,818 B2
• Filed: 10/15/2004
• Issued: 06/05/2007
• Est. Priority Date: 10/15/2004
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Malenfant, Patrick Roland Lucien, Lee, Ji-Ung, Cicha, Walter Vladimir, Li, Yun
• Primary Examiner(s): Estrada; Michelle
• Assistant Examiner(s): Tobergte; Nicholas J.
• Application Number:
  US10/966,793
• Publication Number:
  US 20060081882A1
• Time in Patent Office: 963 Days
• Field of Search: 438/153, 438/154, 438/167, 438/169, 438/172, 438/186, 438/188, 438/197, 438/199, 438/201, 438/FOR.163, 438/149, 257/E51.005, 257/E29.265, 977/742
• US Class Current: 438/149
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H10K 10/466 Lateral bottom-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 10/488 the channel region comprising a layer of composite material having interpenetrating or embedded materials, e.g. a mixture of donor and acceptor moieties, that form a bulk heterojunction
• CPC Class Codes: H10K 71/12 using liquid deposition, e.g. spin coating
• CPC Class Codes: H10K 85/113 Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: H10K 85/221 Carbon nanotubes
• CPC Class Codes: H10K 85/761 Biomolecules or bio-macromolecules, e.g. proteins, chlorophyl, lipids or enzymes
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs

Abstract

The present invention is directed toward field effect transistors (FETs) and thin film transistors (TFTs) comprising carbon nanotubes (CNTs) and to methods of making such devices using solution-based processing techniques, wherein the CNTs within such devices have been fractionated so as to be concentrated in semiconducting CNTs. Additionally, the relatively low-temperature solution-based processing achievable with the methods of the present invention permit the use of plastics in the fabricated devices.

Claims

1. A method comprising the steps of:

a) dispersing a mixture of metallic and semiconducting carbon nanotubes in a solvent comprising a fractionating agent to form a dispersion;

b) centrifuging the dispersion to effect, with the aid of the fractionating agent, a fractionation of carbon nanotubes by electronic type into sediment and supernatant, such that the supernatant becomes enriched in semiconducting carbon nanotubes; and

c) transferring the carbon nanotubes from the supernatant to a substrate to serve as active semiconducting material in a field effect transistor.

2. The method of claim 1, wherein the solvent is selected from the group consisting of CHCl₃, CH₂Cl₂, ODCB, benzene, toluene, xylenes, mesitylene, DMF, DMSO, water, and combinations thereof.

3. The method of claim 1, wherein the fractionating agent is selected from the group consisting of chemical adsorbates, polymeric species, oligomeric species, surfactants, and combinations thereof.

4. The method of claim 3, wherein attached to the fractionating agent is a dendritic species.

5. The method of claim 1, wherein the fractionating agent is a polymeric species.

6. The method of claim 5, wherein the polymeric species is amphiphilic.

7. The method of claim 5, wherein the polymeric species is a conjugated polymer.

8. The method of claim 5, wherein the polymeric species is selected from the group consisting of polythiophenes, polythiophene derivatives, poly(bithiophene-fluorenes) single-stranded DNA, and combinations thereof.

9. The method of claim 5, wherein the polymeric species is P3HT.

10. The method of claim 1, wherein the step of transferring involves a transfer of the supernatant to the substrate followed by a solvent removal process.

11. The method of claim 1, wherein the step of transferring involves isolating carbon nanotubes from the supernatant prior to transferring them to the substrate.

12. The method of claim 1, wherein the step of transferring involves the transfer of carbon nanotubes in a polymeric matrix.

13. The method of claim 1, wherein the active semiconducting material further comprises at least one additional material selected from the group consisting of polymeric material, oligomeric material, aromatic organic molecules. C60, and combinations thereof.

14. The method of claim 13, wherein the additional material dopes the carbon nanotubes in a manner selected from the group consisting of n-doping and p-doping.

15. The method of claim 1, wherein at least some of the carbon nanotubes have been shortened by a process selected from the group consisting of chemical shortening processes, physical cutting processes, and combinations thereof.