Bulk direct gap MoS2 by plasma induced layer decoupling

Patent metadata

Field	Value
Publication number	US-10680403-B2
Application number	US-201515536628-A
Country	US
Kind code	B2
Filing date	Dec 16, 2015
Priority date	Dec 16, 2014
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

Bulk direct transition metal dichalcogenide (TMDC) may have an increased interlayer separation of at least 0.5, 1, or 3 angstroms more than its bulk value. The TMDC may be a bulk direct band gap molybdenum disulfide (MoS2) or a bulk direct band gap tungsten diselenide (WSe 2 ). Oxygen may be between the interlayers. A device may include the TMDC, such as an optoelectronic device, such as an LED, solid state laser, a photodetector, a solar cell, a FET, a thermoelectric generator, or a thermoelectric cooler. A method of making bulk direct transition metal dichalcogenide (TMDC) with increased interlayer separation may include exposing bulk direct TMDC to a remote (aka downstream) oxygen plasma. The plasma exposure may cause an increase in the photoluminescence efficiency of the TMDC, more charge neutral doping, or longer photo-excited carrier lifetimes, as compared to the TMDC without the plasma exposure.

First claim

The invention claimed is:

1. A metal dichalcogenide (TMDC) comprising:
metal dichalcogenide flakes having monolayers with oxygen disposed within interlayers thereof, with an increased interlayer separation of at least 0.5 angstrom more than its bulk value such that the metal dichalcogenide has a bulk direct band gap wherein the metal dichalcogenide flakes have 4 to 15 metal dichalcogenide monolayers.

2. The TMDC of claim 1 wherein the TMDC is a bulk direct band gap molybdenum disulfide (MoS 2 ).

3. The TMDC of claim 2 wherein the increased interlayer separation is at least 1 angstrom.

4. The TMDC of claim 2 wherein the increased interlayer separation is at least 3 angstrom.

5. The TMDC of claim 1 wherein the TMDC is a bulk direct band gap tungsten diselenide (WSe 2 ).

6. A device comprising the TMDC of claim 1 .

7. The device of claim 6 wherein the device is an optoelectronic device.

8. The device of claim 7 wherein the optoelectronic device is an LED.

9. The device of claim 7 wherein the optoelectronic device is a solid state laser.

10. The device of claim 7 wherein the optoelectronic device is a photodetector.

11. The device of claim 7 wherein the optoelectronic device is a solar cell.

12. The device of claim 7 wherein the optoelectronic device is a FET.

13. The device of claim 7 wherein the optoelectronic device is a thermoelectric generator.

14. The device of claim 7 wherein the optoelectronic device is a thermoelectric cooler.

15. A metal dichalcogenide (TMDC) comprising:
metal dichalcogenide flakes having monolayers with oxygen disposed within interlayers thereof, with an increased interlayer separation of at least 0.5 angstrom more than its bulk value such that the metal dichalcogenide has a bulk direct band gap wherein the TMDC is a hulk direct band gap molybdenum disulfide (MoS 2 ) and wherein the increased interlayer separation is at least 3 angstrom.

16. The TMDC of claim 15 wherein the metal dichalcogenide flakes have 4 to 15 metal dichalcogenide monolayers.

17. A device comprising the TMDC of claim 15 .

18. The device of claim 17 wherein the device is an optoelectronic device.

19. The device of claim 18 wherein the optoelectronic device is an LED.

20. The device of claim 18 wherein the optoelectronic device is a solid state laser.

21. The device of claim 18 wherein the optoelectronic device is a photodetector.

22. The device of claim 18 wherein the optoelectronic device is a solar cell.

23. The device of claim 18 wherein the optoelectronic device is a FET.

24. The device of claim 18 wherein the optoelectronic device is a thermoelectric generator.

25. The device of claim 18 wherein the optoelectronic device is a thermoelectric cooler.

26. A metal dichalcogenide (TMDC) comprising:
metal dichalcogenide flakes having monolayers with oxygen disposed within interlayers thereof, with an increased interlayer separation of at least 0.5 angstrom more than its hulk value such that the metal dichalcogenide has a hulk direct band gap wherein the TMDC is a bulk direct band gap tungsten diselenide (WSe 2 ).

27. The TMDC of claim 26 wherein the metal dichalcogenide flakes have 4 to 15 metal dichalcogenide monolayers.

28. A device comprising the TMDC of claim 26 .

29. The device of claim 28 wherein the device is an optoelectronic device.

30. The device of claim 29 wherein the optoelectronic device is an LED.

31. The device of claim 29 wherein the optoelectronic device is a solid state laser.

32. The device of claim 29 wherein the optoelectronic device is a photodetector.

33. The device of claim 29 wherein the optoelectronic device is a solar cell.

34. The device of claim 29 wherein the optoelectronic device is a FET.

35. The device of claim 29 wherein the optoelectronic device is a thermoelectric generator.

36. The device of claim 29 wherein the optoelectronic device is a thermoelectric cooler.

Assignees

• Univ Southern California
• Univ California

Inventors

• Cronin Stephen B
• Dhall Rohan
• Lake Roger
• Li Zhen
• Neupane Mahesh
• Wickramaratne Darshana

Classifications

• H01L31/032

  Electricity · mapped topic

• H01S5/0612

  controlled by temperature · CPC title

• H01L33/26

  Electricity · mapped topic

• H01B1/06

  mainly consisting of other non-metallic substances · CPC title

• C01G39/06

  Sulfides · CPC title