Phase transformation in transition metal dichalcogenides

Patent metadata

Field	Value
Publication number	US-2016181516-A1
Application number	US-201514627296-A
Country	US
Kind code	A1
Filing date	Feb 20, 2015
Priority date	Feb 21, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

Devices including transition metal dichalcognides and methods of forming and operating such devices are disclosed. In one disclosed method, a layer of a transition metal dichalcogenide is provided, and a phase transformation of at least a region of the layer of the transition metal dichalcogenide is induced.

First claim

What is claimed is:

1 . A method of operating an electronic or optoelectronic device, comprising:
providing a layer of a transition metal dichalcogenide; and inducing a phase transformation of at least a region of the layer of the transition metal dichalcogenide.

2 . The method of claim 1 , wherein the device is a memory device, and inducing the phase transformation is carried out to store information according to a change in an electrical or optical property resulting from the phase transformation.

3 . The method of claim 2 , further comprising measuring the electrical or optical property to read the stored information.

4 . The method of claim 1 , wherein the transition metal dichalcogenide has the chemical formula MX 2 , where M is at least one transition metal, and X is at least one of S, Se, and Te.

5 . The method of claim 4 , wherein M is a Group 6 transition metal.

6 . The method of claim 1 , wherein inducing the phase transformation includes inducing a transformation between semiconducting and metallic phases of the transition metal dichalcogenide.

7 . The method of claim 6 , wherein the semiconducting and metallic phases correspond to different crystal structures of the transition metal dichalcogenide.

8 . The method of claim 6 , wherein the phase transformation is characterized by a discontinuity in at least one electrical or optical property of the transition metal dichalcogenide.

9 . The method of claim 1 , wherein inducing the phase transformation includes applying at least one of: (a) a mechanical stimulus; (b) an electrical stimulus; (c) a thermal stimulus; and (d) an optical stimulus to the layer of the transition metal dichalcogenide.

10 . An electronic or optoelectronic device, comprising:
a layer of a transition metal dichalcogenide; and a pair of electrodes connected to the layer of the transition metal dichalcogenide.

11 . The device of claim 10 , wherein the device is a memory device, and the pair of electrodes is configured to apply an electrical stimulus to the layer of the transition metal dichalcogenide to induce a phase transformation of at least a region of the layer of the transition metal dichalcogenide, thereby storing information according to a change in an electrical property resulting from the phase transformation.

12 . The device of claim 10 , wherein the device is a transistor device, the pair of electrodes corresponds to a source electrode and a drain electrode, the transistor device includes a channel connected between the source electrode and the drain electrode, the channel includes the layer of the transition metal dichalcogenide, and the transistor device further includes a gate electrode connected to the channel.

13 . The device of claim 12 , wherein the gate electrode is configured to apply an electrical stimulus to the layer of the transition metal dichalcogenide to induce a phase transformation of at least a region of the layer of the transition metal dichalcogenide.

14 . The device of claim 10 , wherein the transition metal dichalcogenide is selected from at least one of MoTe 2 , MoSe 2 , MoS 2 , WTe 2 , WSe 2 , WS 2 , alkali metal-doped MoTe 2 , alkali metal-doped MoSe 2 , alkali metal-doped MoS 2 , alkali metal-doped WTe 2 , alkali metal-doped WSe 2 , and alkali metal-doped WS 2 .

15 . An optical switching device, comprising:
a substrate; a patterned metal layer disposed over the substrate; a layer of a transition metal dichalcogenide disposed over the substrate and adjacent to the patterned metal layer; and an electrical source connected to the layer of the transition metal dichalcogenide.

16 . The device of claim 15 , wherein the electrical source is configured to apply an electrical stimulus to the layer of the transition metal dichalcogenide to induce a phase transformation of at least a region of the layer of the transition metal dichalcogenide.

17 . The device of claim 15 , wherein the transition metal dichalcogenide has the chemical formula MX 2 , where M is at least one Group 6 transition metal, and X is at least one of S, Se, and Te.

18 . The device of claim 15 , wherein the patterned metal layer includes metal particles having at least one dimension in a range of up to 200 nm.

19 . The device of claim 15 , wherein the layer of the transition metal dichalcogenide is disposed between the substrate and the patterned metal layer.

20 . The device of claim 15 , wherein the layer of the transition metal dichalcogenide is disposed over the patterned metal layer.

Assignees

• Univ Leland Stanford Junior

Inventors

• Reed Evan J
• Duerloo Karel-Alexander
• Li Yao

Classifications

• G11C13/047

  using electro-optical elements (G11C13/042 takes precedence) · CPC title

• G02F1/0054

  Structure, phase transitions, NMR, ESR, Moessbauer spectra · CPC title

• G02F1/03

  based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect (G02F1/061 takes precedence) · CPC title

• G02F2203/11

  involving infrared radiation · CPC title

• G11C13/0004 Primary

  comprising amorphous/crystalline phase transition cells · CPC title