Vapor-trapping growth of single-crystalline graphene flowers

Patent metadata

Field	Value
Publication number	US-9627485-B2
Application number	US-201414214173-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Mar 15, 2013
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A method for growing a graphene layer on a metal foil includes placing a vessel into a chemical vapor deposition chamber, the vessel having a metal foil positioned therein. The method includes evacuating the chemical vapor deposition chamber, introducing hydrogen gas into the chamber to achieve a first pressure less than atmospheric pressure, heating the atmosphere in the chamber to anneal the metal foil, introducing methane and hydrogen into the chamber to achieve a second pressure less than atmospheric pressure.

First claim

What is claimed is:

1. A method comprising:
placing a vessel comprising a quartz tube having an open end into a chemical vapor deposition chamber, wherein metal foil is positioned into the vessel, and wherein the open end of the vessel is directly facing and closer to a first opening of the chemical vapor deposition chamber than a closed end of the vessel is to the first opening;
evacuating the chemical vapor deposition chamber;
flowing hydrogen gas through the chamber from the first opening of the chamber to a second opening of the chamber to achieve a first pressure less than atmospheric pressure;
heating the atmosphere in the chamber to anneal the metal foil;
flowing methane and hydrogen through the chamber from the first opening of the chamber to the second opening of the chamber to achieve a second pressure less than atmospheric pressure; and
depositing carbon on the metal foil to yield a single-crystalline graphene layer on the metal foil.

2. The method of claim 1 , wherein the methane and hydrogen introduced into the chamber do not flow through the vessel.

3. The method of claim 2 , wherein the methane and hydrogen introduced into the chamber diffuse into the vessel.

4. The method of claim 1 , wherein a local environment between the metal foil and an interior of the vessel is different from an environment inside the chamber, and wherein the metal foil is a copper foil.

5. The method of claim 4 , wherein the vessel reduces a supply of carbon to the metal foil and creates a quasi-static reactant gas distribution.

6. The method of claim 1 , wherein the graphene layer is in a shape of a four-lobed flower, a six-lobed flower, or a combination thereof.

7. The method of claim 1 , wherein a dimension of the graphene layer on the metal foil is less than or about 100 μm.

8. The method of claim 6 , wherein lobes of the four-lobed flower, the six-lobed flower, or the combination thereof are a single-layer graphene.

9. The method of claim 6 , wherein a center of the four-lobed flower, the six-lobed flower, or the combination thereof is a bilayer graphene.

10. The method of claim 1 , further comprising adjusting a total pressure, a methane to hydrogen flow rate ratio, or both to obtain a desired morphology.

11. The method of claim 1 , wherein a ratio of a flow rate of the methane to a flow rate of the hydrogen is between 1:10 to 1:20.

12. The method of claim 1 , wherein a total pressure of the methane and hydrogen is less than 200 mTorr.

13. The method of claim 1 , further comprising removing the graphene layer from the metal foil.

14. The method of claim 1 , wherein the graphene layer produces one set of symmetric six-fold electron diffraction patterns oriented in a same direction.

15. A method of forming a field effect transistor, the method comprising:
providing a silicon substrate;
providing a thermal oxide layer on the silicon substrate;
transferring the graphene layer formed by the method of claim 1 from the metal foil onto the thermal oxide layer to form a graphene channel;
depositing a source electrode at one end of the graphene channel; and
depositing a drain electrode at another end of the graphene channel.

Assignees

• Zhou Chongwu
• Zhang Yi
• Zhang Luyao
• Univ Southern California

Inventors

• Zhou Chongwu
• Zhang Yi
• Zhang Luyao

Classifications

• H10W10/181

  Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers · CPC title

• H10P90/1906

  Preparing SOI wafers · CPC title

• C01B2204/32

  Size or surface area · CPC title

• C01B2204/02

  Single layer graphene · CPC title

• H01L29/78684

  Electricity · mapped topic