Method for preparing ultrathin two-dimensional nanosheets and applications thereof

Patent metadata

Field	Value
Publication number	US-2020403111-A1
Application number	US-202016905995-A
Country	US
Kind code	A1
Filing date	Jun 19, 2020
Priority date	Jun 19, 2019
Publication date	Dec 24, 2020
Grant date	—

Abstract

A method for preparing an ultrathin two-dimensional (2D) monocrystalline nanosheet, the method including: 1) placing BiX 3 powder where X=I, Br, or Cl in a crucible, and putting the crucible on a first heating zone of a furnace disposed at a gas inlet of a quartz tube; placing substrates covered with metal sheets on a second heating zone of the furnace disposed at a gas outlet of the quartz tube; 2) vacuumizing the quartz tube; pumping Ar gas into the quartz tube until the air pressure is 101.325 kPa; pumping a carrier gas into the quartz tube; and 3) heating and maintaining the second heating zone; heating the first heating zone for BiX 3 evaporation until producing chemical reaction between BiX 3 and the metal sheets, and preparing ultrathin 2D nanosheets on the substrates simultaneously; and cooling the substrate naturally to 15-30° C.

First claim

What is claimed is:

1 . A method, comprising:
placing BiX 3 powder where X=I, Br, or Cl in a crucible, and putting the crucible on a first heating zone of a furnace disposed at a gas inlet of a quartz tube; placing substrates covered with metal sheets on a second heating zone of the furnace disposed at a gas outlet of the quartz tube; vacuumizing the quartz tube by a mechanical pump; pumping Ar gas into the quartz tube until a gas pressure is equal to 101.325 kPa; pumping a carrier gas into the quartz tube and adjusting and maintaining a steady flow rate of the carrier gas; and heating and maintaining the second heating zone; heating the first heating zone to evaporate BiX 3 until the ultrathin 2D nanosheets are formed on the substrate; and cooling the substrate naturally to 15-30° C.

2 . The method of claim 1 , wherein the metal sheets are unoxidized transition or naturally oxidized transition; the metal sheets and the substrates construct micro-nano scale confined space, and a gap distance between the metal sheets and the substrates is 0-100 microns.

3 . The method of claim 2 , wherein the transition metal sheets are copper sheets or iron sheets.

4 . The method of claim 1 , wherein the naturally oxidized transition metal sheets are oxidized in the air at 15-30° C. for 1-2 days.

5 . The method, comprising:
1) placing BiBr 3 powder in a crucible, and putting the crucible on a first heating zone of a furnace disposed at a gas inlet of a quartz tube; placing substrates covered with copper sheets on a second heating zone of the furnace disposed at a gas outlet of the quartz tube; wherein a confined spacing gap between the copper sheets and the substrates is 0-100 μm; 2) vacuumizing the quartz tube to less than 0.1 Pa; pumping Ar gas into the quartz tube until an air pressure is equal to one atmosphere pressure; pumping mixed gas of Ar and H 2 to the quartz tube and adjusting and maintaining a steady flow rate of the mixed gas; and 3) heating the second heating zone to a temperature of 275-325° C. and keeping the temperature for 10-60 min; heating the first heating zone to 200-275° C. for 3-20 min until producing chemical reaction between BiBr 3 and metal sheets, and preparing ultrathin 2D nanosheets on the substrates simultaneously; and cooling the substrate naturally to 15-30° C., thereby yielding a two-dimensional ultrathin monocrystalline CuBr nanosheet.

6 . The method of claim 5 , wherein the substrates in 1) are mica or graphene substrate and a mass of the BiBr 3 powder is 2-200 mg.

7 . The method of claim 5 , wherein the H 2 in 2) is 0-10% (v/v) in the mixed gas and a flow velocity of the mixed gas is about 50-100 sccm.

8 . A two-dimensional ultrathin monocrystalline CuBr nanosheet prepared according to the method of claim 5 , wherein a thickness of the two-dimensional ultrathin monocrystalline CuBr nanosheet is 0.9-200 nm and a sheet size thereof is 2-150 μm.

9 . A method for preparing a photodetector based on the two-dimensional ultrathin monocrystalline CuBr nanosheet of claim 8 , the method comprising: depositing a silver electrode with a thickness of 25-100 nm using a copper mesh as a mask on the two-dimensional ultrathin monocrystalline CuBr nanosheet.

10 . A method, comprising:
1) placing BiI 3 powder in a crucible, and putting the crucible on a first heating zone of a furnace disposed at a gas inlet of a quartz tube; placing substrates covered with naturally oxidized iron sheets on a second heating zone of the furnace disposed at a gas outlet of the quartz tube; 2) vacuumizing the quartz tube to less than 1 Pa; pumping Ar gas into the quartz tube until an air pressure is equal to one atmosphere pressure; continuously pumping the Ar gas to the quartz tube with a flow velocity of 10-75 sccm; and 3) heating the second heating zone to a temperature of 370-450° C. and keeping the temperature for 10-60 min; heating the first heating zone to 450-520° C. for 5-20 min until producing chemical reaction between BiI 3 and metal sheets, and preparing ultrathin 2D nanosheets on the substrates simultaneously; and cooling the substrate naturally to 15-30° C., thereby yielding a two-dimensional ultrathin monocrystalline Fe 3 O 4 nanosheet.

11 . The method of claim 10 , wherein a mass of the BiI 3 powder in 1) is 1-20 mg and the substrates are mica.

12 . The method of claim 10 , wherein the naturally oxidized iron sheets in 1) is obtained by placing iron sheets in the air with 15-30° C. for 1 to 2 days.

13 . A two-dimensional ultrathin monocrystalline Fe 3 O 4 nanosheet prepared according to the method of claim 10 , wherein a thickness of the two-dimensional ultrathin monocrystalline Fe 3 O 4 nanosheet is 1.95-100 nm and a sheet size thereof is 1-20 nm.

14 . A method for preparing the two-dimensional ultrathin monocrystalline Fe 3 O 4 nanosheet of claim 13 , the method comprising: transferring the Fe 3 O 4 nanosheet from a mica substrate to an Si/SiO 2 substrate; depositing an electrode by electron beam exposure and thermal evaporation, the electrode comprising a Cr with a thickness of 1-10 nm and an Au with a thickness of 10-100 nm.

15 . A method, comprising:
1) placing BiBr 3 powder in a crucible, and putting the crucible on a first heating zone of a furnace disposed at a gas inlet of a quartz tube; placing substrates covered with naturally oxidized copper sheets on a second heating zone of the furnace disposed at a gas outlet of the quartz tube; 2) vacuumizing the quartz tube to less than 0.1 Pa; pumping Ar gas into the quartz tube until an air pressure is equal to one atmosphere pressure; continuously pumping the Ar gas to the quartz tube with a flow velocity of 25-50 sccm; and 3) heating the second heating zone to a temperature of 380-400° C. and keeping the temperature for 1-60 min; heating the first heating zone to 220-275° C. for 5-30 min until producing chemical reaction between BiI 3 and metal sheets, and preparing ultrathin 2D nanosheets on the substrates simultaneously; and cooling the substrate naturally to 15-30° C., thereby yielding a two-dimensional ultrathin monocrystalline BiOBr nanosheet.

16 . The method of claim 15 , wherein a mass of the BiBr 3 powder in 1) is 2-50 mg.

17 . The method of claim 15 , wherein the naturally oxidized copper sheets in 1) is obtained by placing the copper sheets in the air with 15-30° C. for 1 to 2 days.

18 . The method of claim 15 , wherein the cooling in 3) is natural cooling or rapid cooling, and a rate of the rapid cooling is over 50° C./min.

19 . A two-dimensional ultrathin monocrystalline BiOBr nanosheet prepared according to the method of claim 15 , wherein a growth crystal surface of the two-dimensional ultrathin monocrystalline BiOBr nanosheet is (001), a thickness is 0.57-200 nm, and a sheet size is 0.5-70 nm.

20 . A method for preparing a photodetector based on the two-dimensional ultrathin monocrystalline BiOBr nanosheet of claim 19 , the method comprising: transferring the BiOBr nanosheet with a thickness of 0.57 nm-20 nm onto a silicon substrate using a wet method, and manufacturing an electrode by electron beam lithography and thermal evaporation.

Assignees

• Univ Electronic Sci & Tech China

Inventors

• Xiong Jie
• Gong Chuanhui
• Wang Yang
• Rao Gaofeng
• Yin Chujun
• Yan Chaoyi
• Chu Junwei
• Huang Jianwen
• Zhang Miao
• Chen Xinrui
• Liu Yuqing
• Wu Chunyang
• Wang Xianfu
• Dai Liping
• Zhang Wanli
• Li Yanrong

Classifications

• H10F77/20

  Electrodes · CPC title

• H10F77/12

  Active materials · CPC title

• H10F30/10

  the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors · CPC title

• H10F71/00 Primary

  Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00) · CPC title

• H10F77/16 Primary

  Material structures, e.g. crystalline structures, film structures or crystal plane orientations · CPC title