Large-scale synthesis of 2d semiconductors by epitaxial phase conversion

Patent metadata

Field	Value
Publication number	US-2020357635-A1
Application number	US-201816960697-A
Country	US
Kind code	A1
Filing date	Dec 12, 2018
Priority date	Jan 22, 2018
Publication date	Nov 12, 2020
Grant date	—

Abstract

There is a method for forming an oxide or chalcogenide 2D semiconductor. The method includes a step of growing on a substrate, by a deposition method, a precursor epitaxy oxide or chalcogenide film; and a step of sulfurizing the precursor epitaxy oxide or chalcogenide film, by replacing the oxygen atoms with sulfur atoms, to obtain the oxide or chalcogenide 2D semiconductor. The oxide or chalcogenide 2D semiconductor has an epitaxy structure inherent from the precursor epitaxy oxide or chalcogenide film.

First claim

1 . A method for forming an oxide or chalcogenide 2D semiconductor, the method comprising:
growing on a substrate, by a deposition method, a precursor epitaxy oxide or chalcogenide film; and sulfurizing the precursor epitaxy oxide or chalcogenide film, by replacing the oxygen atoms with sulfur atoms, to obtain the oxide or chalcogenide 2D semiconductor, wherein the oxide or chalcogenide 2D semiconductor has an epitaxy structure inherent from the precursor epitaxy oxide or chalcogenide film.

2 . The method of claim 1 , wherein the precursor epitaxy oxide or chalcogenide film is a precursor single crystal MoO 2 film, the oxide or chalcogenide 2D semiconductor is a MoS 2 semiconductor, and the deposition method is one of pulse laser deposition, metalorganic vapor phase epitaxy or molecular beam epitaxy.

3 . The method of claim 2 , further comprising:
providing the substrate inside a chamber of a pulse laser deposition (PLD) system; placing a target material on a target support underneath the substrate with a certain distance inside the PLD chamber; and irradiating with a laser beam the target material to ablate atoms of the target material, wherein the ablated atoms travel to the substrate and form the precursor single crystal MoO 2 film.

4 . The method of claim 3 , wherein the target material is MoO 3 .

5 . The method of claim 3 , wherein the substrate is located above the target support.

6 . The method of claim 3 , wherein the substrate and the target support rotate.

7 . The method of claim 3 , wherein the substrate rotates with an angular speed between 20 and 40° per second.

8 . The method of claim 3 , further comprising:
providing an O 2 atmosphere inside the PLD chamber.

9 . The method of claim 8 , further comprising:
cooling down the MoO 2 film.

10 . The method of claim 3 , further comprising:
activating the laser beam about 100 times to generate the precursor single crystal MoO 2 film.

11 . The method of claim 3 , wherein a thickness of the precursor single crystal MoO 2 film is about 3 nm.

12 . The method of claim 3 , further comprising:
placing the precursor single crystal MoO 2 film into a middle zone of a tube furnace having three different zones; providing sulfur powder into a first zone of the tube furnace, upstream the middle zone; supplying a carrier gas from the first zone towards the middle zone; and heating the middle zone of the tube furnace to evaporate the sulfur.

13 . The method of claim 12 , wherein the sulfur is transported by the carrier gas from the first zone to the middle zone and the sulfur replaces the oxygen in the precursor single crystal MoO 2 film.

14 . The method of claim 13 , wherein the precursor single crystal MoO 2 film becomes a single crystal MoS 2 2D film as a result of the replacement of oxygen atoms with sulfur atoms.

15 . The method of claim 12 , wherein the step of heating is performed to increase a temperature of the middle zone from room temperature to about 900° C.

16 . The method of claim 15 , wherein the step of heating is performed at a rate of about 20° C./min.

17 . The method of claim 2 , wherein the MoS 2 2D semiconductor has between 5 and 10 layers.

18 . A MoS 2 electrode comprising:
a substrate; and a single crystal MoS 2 film formed directly on the substrate, wherein the single crystal MoS 2 film is formed by pulsed laser deposition (PLD), from a precursor single crystal MoO 2 film, and the precursor single crystal MoO 2 film is sulfurized to replace the oxygen atoms with sulfur atoms to obtain the MoS 2 film.

19 . The MoS 2 electrode of claim 18 , wherein the MoS 2 electrode has between 5 and 10 layers.

20 . A thin film transistor comprising:
a substrate; a single crystal MoS 2 film formed on the substrate; a drain electrode and a source electrode formed on the substrate and sandwiching the single crystal MoS 2 electrode; a dielectric layer formed over the drain electrode, the source electrode, and the single crystal MoS 2 electrode; and a gate electrode formed over the dielectric layer, wherein the single crystal MoS 2 electrode is formed from a precursor single crystal MoO 2 film by pulsed laser deposition (PLD), and the precursor single crystal MoO 2 film is sulfurized to replace the oxygen atoms with sulfur atoms.

21 . The thin film transistor of claim 19 , wherein the MoS 2 electrode has between 5 and 10 layers.

Assignees

• Univ King Abdullah Sci & Tech

Inventors

• Xu Xiangming
• Alshareef Husam Niman

Classifications

• H10P14/6329 Primary

  using physical ablation of a target, e.g. physical vapour deposition or pulsed laser deposition · CPC title

• C30B33/00

  After-treatment of single crystals or homogeneous polycrystalline material with defined structure (C30B31/00 takes precedence) · CPC title

• C23C14/3435

  Applying energy to the substrate during sputtering · CPC title

• C30B23/02 Primary

  Epitaxial-layer growth · CPC title

• C23C14/5866

  Treatment with sulfur, selenium or tellurium · CPC title