Thermal stable, one-dimensional hexagonal-phase vanadium sulfide nanowires and methods for preparing the same

Patent metadata

Field	Value
Publication number	US-12590384-B2
Application number	US-202318523934-A
Country	US
Kind code	B2
Filing date	Nov 30, 2023
Priority date	Nov 30, 2023
Publication date	Mar 31, 2026
Grant date	Mar 31, 2026

Abstract

The present invention provides a general salt-assisted chemical vapor deposition (SA-CVD) synthetic method for the high-yield preparation of 1D hexagonal-phase M x V 6 S 8 (M=K, Rb, Cs) and K x V 6 S y Se 8-y nanowires. The resulting nanowires exhibit typical metallic properties, which can be used as a good van der Waals contact for achieving high-performance fermi level pinning free transistors. The present synthesis method allows a more systematic investigation of the intrinsic properties of hexagonal-phase V 6 S 8 structures.

First claim

What is claimed is:

1 . A thermal stable, one dimensional hexagonal-phase M x V y S z nanowire, wherein
M=K, Rb, Cs; x=0.2 or 1.12; y=6; z=8, wherein the thermal stable, one dimensional hexagonal-phase M x V y S z nanowire, has c-axis-aligned hexagonal channels, and wherein the thermal stable, one dimensional hexagonal-phase M x V y S z nanowire exhibits an unchanged Raman spectrum in a temperature range of 30 to 300° C.

2 . The thermal stable, one dimensional hexagonal-phase M x V y S z nanowire of claim 1 , wherein the c-axis-aligned hexagonal channels have diameters in a range of 5 Å to 10 Å.

3 . The thermal stable, one dimensional hexagonal-phase M x V y S z nanowire of claim 1 , wherein the thermal stable, one dimensional hexagonal-phase M x V y S z nanowire functions as effective van der Waals contacts for MoS 2 -based field-effect transistors, with good ohmic contact, large charge mobility, and reduced Fermi-level pinning effect.

4 . The thermal stable, one dimensional hexagonal-phase M x V y S z nanowire of claim 1 , wherein the M x V y S z nanowire has a thickness ranging from 1-15 nm.

5 . The thermal stable, one dimensional hexagonal-phase M x V y S z nanowire of claim 1 , wherein the M x V y S z nanowire is K 0.2 V 6 S 8 , exhibiting five distinctive Raman peaks recorded at 532 nm, comprising 169.4, 221.5, 326.7, 340.0, and 374.1 cm −1 , respectively.

6 . A thermal stable, one dimensional hexagonal-phase K x V 6 S y Ses 8-y nanowire, wherein
x=0.68 or 1.34; y=7.02 or 6.79, wherein the thermal stable, one dimensional hexagonal-phase M x V y S z nanowire has c-axis-aligned hexagonal channels, and wherein the thermal stable, one dimensional hexagonal-phase K x V 6 S y Se 8-y nanowire exhibits an unchanged Raman spectrum in a temperature range of 30 to 300° C.

7 . The thermal stable, one dimensional hexagonal-phase K x V 6 S y Se 8-y nanowire of claim 6 , wherein the c-axis-aligned hexagonal channels have diameters in a range of 5 Å to 10 Å.

8 . The thermal stable, one dimensional hexagonal-phase K x V 6 S y Se 8-y nanowire of claim 6 , wherein the thermal stable, one dimensional hexagonal-phase K x V 6 S y Se 8-y nanowire functions as effective van der Waals contacts for MoS 2 -based field-effect transistors, with good ohmic contact, large charge mobility, and reduced Fermi-level pinning effect.

9 . The thermal stable, one dimensional hexagonal-phase K x V 6 S y Se 8-y nanowire of claim 7 , wherein the K x V 6 S y Se 8-y nanowire is K 0.68 V 6 S 7.02 Se 0.98 , exhibiting five distinctive Raman peaks recorded at 532 nm, comprising 165.2, 221.3, 328.4, 337.9, and 375.7 cm −1 , respectively.

10 . The thermal stable, one dimensional hexagonal-phase K x V 6 S y Se 8-y nanowire of claim 7 , wherein the K x V 6 S y Se 8-y nanowire is K 1.34 V 6 S 6.79 Se 1.21 , exhibiting five distinctive Raman peaks recorded at 532 nm, comprising 157.5, 213.6, 328.4, 337.9, and 370.1 cm −1 , respectively.

11 . A salt-assisted method for synthesizing one-dimensional hexagonal-phase vanadium sulfide nanowires on a substrate, comprising the steps of:
preparing a substrate; providing a precursor by mixing vanadium (V) and sulfur(S) compounds; introducing a metal salt to the precursor via a chemical vapor deposition (SA-CVD) method to obtained a mixture; transferring the mixture to a quartz boat and covering two pieces of fresh-cleaved fluorophlogopite mica substrates on top of loaded mixture; transferring the quartz boat to the center of a quartz tube, and then introducing Ar and H 2 to provide an optimal synthesis atmosphere; heating the quartz tube and then cooling the quartz boat down to room temperature; and growing the one dimensional hexagonal-phase M x V 6 S 8 nanowires and K x V 6 S y S 8-y nanowires on the substrate.

12 . The method of claim 11 , wherein the ratio between the precursor and the metal salt is in a range of 1:1 to 1:1.5.

13 . The method of claim 11 , wherein step of providing a precursor comprises mixing V 2 S 3 powders and S powders.

14 . The method of claim 11 , wherein the substrate comprises a mica substrate.

15 . The method of claim 11 , wherein the metal salt is selected from the group consisting of KCI, K 2 S, K 2 CO 3 , KHCO 3 , K 2 C 2 O 4 ·H 2 O, Rb 2 CO 3 , and Cs 2 CO 3.

16 . The method of claim 11 , wherein the quartz tube is purged with 500 s.c.c.m for 20 minutes in advance to remove internal air and moisture.

17 . The method of claim 11 , wherein the flow rate ratio between the Ar and H 2 is 4:1.

18 . The method of claim 11 , wherein the precursor further comprises Selenium (Se) compounds.

Assignees

• Univ City Hong Kong

Inventors

• Zhang Hua
• Ren Yi

Classifications

• C30B29/46

  Sulfur-, selenium- or tellurium-containing compounds · CPC title

• C30B29/62

  Whiskers or needles · CPC title

• B82Y40/00 Primary

  Manufacture or treatment of nanostructures · CPC title

• C30B25/005 Primary

  Growth of whiskers or needles · CPC title

• C30B29/60

  characterised by shape · CPC title