Process for scalable synthesis of molybdenum disulfide monolayer and few-layer films

Patent metadata

Field	Value
Publication number	US-9527062-B2
Application number	US-201414274154-A
Country	US
Kind code	B2
Filing date	May 9, 2014
Priority date	May 9, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

The present disclosure relates to nanosheet synthesis. More particularly, the present disclosure relates to molybdenum sulfide (MoS 2 ) atomic thin films and hydrogen evolution reactions. In one or more embodiments, a synthesis process may include sublimation of sulfur and MoCl 5 , reaction of MoCl 5 and S to produce gaseous MoS 2 species, transfer of the MoS 2 species by carrier gas, diffusion of MoS 2 species from the gas phase onto receiving substrates, and precipitation of MoS 2 on the substrates.

First claim

What is claimed is:

1. A synthesis process comprising:
sublimation of sulfur and MoCl 5 ;
reaction of MoCl 5 and S to produce gaseous MoS 2 species;
transfer of the MoS 2 species by carrier gas;
diffusion and precipitation of MoS 2 species from the gas phase onto a substrate under suitable conditions that one to four layer(s) of MoS 2 form on the substrate,
wherein the substrate is highly ordered pyrolytic graphite (HOPG).

2. The synthesis process of claim 1 , wherein MoCl 5 is reacted with sulfur at a temperature of about 300° C. to about 1000° C. to give rise to MoS 2 on the substrate.

3. The synthesis process of claim 2 , wherein MoCl 5 is reacted with sulfur at a temperature of about 600° C. to about 900° C. to give rise to MoS 2 on the substrate.

4. The synthesis process of claim 1 , wherein one layer of MoS 2 is formed on the substrate.

5. The synthesis process of claim 1 , wherein two layers of MoS 2 are formed on the substrate.

6. The synthesis process of claim 1 , wherein four layers of MoS 2 are formed on the substrate.

7. A method of producing hydrogen which comprises contacting a suitable reactant under appropriate conditions with the layered MoS 2 substrate prepared by the synthesis process of claim 1 .

8. A method of making a large-area MoS 2 thin film on a surface of a substrate, the method comprising the steps of:
reacting MoCl 5 with a stoichiometric excess of S in a reactor at an elevated temperature to produce gaseous MoS 2 ,
depositing the gaseous MoS 2 at a pressure onto the surface of the substrate;
wherein the amount of the MoCl 5 and the pressure are controlled to produce the large-area MoS 2 thin film on the surface of the substrate; and
wherein the substrate is selected from the group consisting of silicon, silicon oxide, sapphire, graphite, and a combination thereof.

9. The method of claim 8 , wherein the large-area MoS 2 thin film consists of about 1-4 layers of MoS 2 .

10. The method of claim 8 , wherein the large-area MoS 2 thin film consists of a monolayer or a bilayer of MoS 2 .

11. The method of claim 8 , wherein the elevated temperature is about 300° C. to about 1000° C.

12. The method of claim 8 , wherein the pressure is about 2 Torr to 10 Torr.

13. The method of claim 8 , wherein the large-area MoS 2 thin film has an area of about 1 cm 2 or more.

14. The method of claim 8 , wherein the large-area MoS 2 thin film has an area of about 1 cm 2 to about 3 cm 2 .

15. The method of claim 8 , wherein the large-area MoS 2 thin film has a Raman spectra with an E 2g band associated with in-plane vibration of Mo in the MoS 2 thin film, and the full width at half maximum of the E 2g peak is about 4.2 cm −1 or less.

16. The method of claim 8 , wherein the large-area MoS 2 thin film has an average thickness of about 0.68 nm to about 2.54 nm.

17. The method of claim 8 , wherein the large-area MoS 2 thin film has a Raman spectra with an A 1g band associated with out-of-plane vibration of sulfur atoms in the MoS 2 thin film and an E 2g band associated with in-plane vibration of Mo in the MoS 2 thin film, and
wherein there is a frequency difference in the A 1g band and the E 2g band of about 20.2 cm −1 to about 24.0 cm −1 .

18. The method of claim 8 , wherein the large-area MoS 2 thin film has a roughness of less than 0.2 nm.

19. The method of claim 8 , wherein the method further comprises balancing the partial pressure of the gaseous MoS 2 and the vapor pressure of the MoS 2 thin film on the substrate to produce the large-area MoS 2 thin film on the surface of the substrate consisting of 1-4 layers of MoS 2 .

20. The method of claim 8 , wherein the molar ratio of the S to the MoCl 5 is greater than 1000:1.

Assignees

• Univ North Carolina State

Inventors

• Iezzi Brian C
• Li Yanpeng
• Cao Linyou
• Yu Yifei

Classifications

• B01J23/28

  Molybdenum · CPC title

• B01J37/0238

  via the gaseous phase-sublimation · CPC title

• C25B1/04

  by electrolysis of water · CPC title

• B01J27/051 Primary

  Molybdenum · CPC title

• B01J35/004

  Operations & Transport · mapped topic