Graphene transparent conductive electrode

Patent metadata

Field	Value
Publication number	US-2017057827-A1
Application number	US-201514843125-A
Country	US
Kind code	A1
Filing date	Sep 2, 2015
Priority date	Sep 2, 2015
Publication date	Mar 2, 2017
Grant date	—

Abstract

Methods of fabricating graphene for device application are described herein. The method comprises growing a graphene film on a copper substrate using chemical vapor deposition (CVD), transferring the graphene film from the copper substrate to a device substrate, doping the graphene film with gold(III) chloride (AuCl3); and patterning the graphene film. The graphene film has a transmittance of at least 97% in visible to infrared range and a sheet resistance of less than 200 Ohms per square. The graphene film can be used as a transparent conductive electrode in, among others, a microshutter array on a space telescope.

First claim

What is claimed is:

1 . A method of fabricating graphene for device application, the method comprising:
growing a graphene film on a copper substrate using chemical vapor deposition (CVD); transferring the graphene film from the copper substrate to a device substrate; doping the graphene film with gold(III) chloride (AuCl 3 ); and patterning the graphene film.

2 . The method of claim 1 , wherein the growing the graphene film on the copper substrate further comprises:
heating the copper substrate in a CVD reactor to a temperature of about 850° C. to about 1000° C. under an ambient pressure of hydrogen (H 2 ), or argon (Ar), or a mixture thereof; and introducing reactions gas mixtures to the cooper substrate in the CVD reactor, wherein the reaction gas mixtures include flowing methane (CH 4 ) of about 1 to about 20 standard cubic centimeters per minute (sccm), flowing H 2 of about 5 to about 50 sccm, and flowing Ar of about 20 to about 1000 sccm, and wherein said introducing reaction gas mixture is carried out for 30 minutes to 60 minutes.

3 . The method of claim 1 , further comprising:
cooling down the copper substrate at a rate of 25° C. per minute to 35° C. per minute to about 300° C.; and cooling down the copper substrate naturally from about 300° C. to a room temperature.

4 . The method of claim 1 , where the transferring the graphene film from the copper substrate to the device substrate further comprises:
attaching a polymer support to the graphene film on the copper substrate to form a stack; removing the copper substrate from the stack in a copper etchant; attaching a device substrate to the graphene film; and removing the polymer support.

5 . The method of claim 4 , wherein the attaching the polymer support to the graphene film comprises spin-casting a polymer material onto the graphene film.

6 . The method of claim 4 , wherein the device substrate comprises a silicon dioxide substrate.

7 . The method of claim 1 , wherein the doping the graphene film with AuCl 3 comprises:
spinning a AuCl 3 solution onto the graphene film, wherein the AuCl 3 solution has a concentration of 0.001 mole per liter to 0.05 mole per liter of AuCl 3 in a nitromethane (CH 3 NO 2 ) solvent, and wherein said spinning is carried out at 2000 revolutions per minute for about 60 seconds; and drying the nitromethane solvent.

8 . The method of claim 1 , wherein the transferring the graphene film and the doping the graphene film comprise:
attaching a polymer support to the graphene film grown on the copper substrate to form a stack; removing the copper substrate from the stack in a copper etchant; cleaning the graphene film in deionized water; doping the graphene film with AuCl 3 in a AuCl 3 solution; attaching a device substrate to the graphene film; and removing the polymer support.

9 . The method of claim 1 , wherein the patterning the graphene film comprises etching the graphene film with oxygen plasma.

10 . The method of claim 9 , wherein the patterning the graphene film comprises using a photolithography mask when etching the graphene film.

11 . A graphene film doped with AuCl 3 that has a transmittance of at least 97% in visible to infrared range and a sheet resistance of less than 200 Ohms per square.

12 . The graphene film of claim 11 , wherein the graphene film is a monolayer graphene.

13 . The graphene film of claim 11 , wherein the sheet resistance is less than 100 Ohms per square.

14 . The graphene film of claim 11 , wherein the sheet resistance is less than 60 Ohms per square.

15 . A device comprising a graphene transparent conductive electrode, wherein the graphene transparent conductive electrode comprises a graphene film doped with AuCl 3 , and wherein the graphene film has a transmittance of at least 97% in visible to infrared range and a sheet resistance of less than 200 Ohms per square.

16 . The device of claim 15 , wherein the sheet resistance is less than 60 Ohms per square.

17 . The device of claim 15 , wherein the device comprises a transparent substrate in a microshutter array.

18 . The device of claim 16 , wherein the microshutter array is on a space telescope.

19 . The device of claim 15 , wherein the device comprises a photovoltaic device.

20 . The device of claim 15 , wherein the device comprises a field effect transistor (FET).

Assignees

• Nasa

Inventors

• Sultana Mahmooda
• Li Mary J
• Hess Larry A

Classifications

• H10P50/267

  using plasmas · CPC title

• H10P70/27

  during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers · CPC title

• H10P32/30

  Diffusion for doping of conductive or resistive layers · CPC title

• H10P14/43

  Chemical deposition, e.g. chemical vapour deposition [CVD] · CPC title

• H10D64/0113

  the conductive layers comprising highly doped semiconductor materials, e.g. polysilicon layers or amorphous silicon layers · CPC title