JP3921538B2 - Method for producing single crystal zinc selenide nanowire - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing single crystal zinc selenide nanowires.
[0002]
[Prior art]
Selenides having a wide band gap as a II-VI group semiconductor material have been widely studied for their applications in the fields of light-emitting devices, solar cells, sensors, optical recording materials, and the like. Zinc selenide nanowires and nanorods having a one-dimensional structure are manufactured by a method using a template, a method using heating in a solvent, and a method using a catalyst such as gold (for example, Non-Patent Documents 1, 2, and 3). reference.).
[0003]
[Non-Patent Document 1]
N. Kouklin, et al., Applied Physics Letters 79, 4423, 2001 [Non-patent Document 2]
W. Wang, et al., Inorganic Chemical Communications Inorg. Chem. Commun. "Volume 2, p. 83, 1999 [Non-Patent Document 3]
Y. Xia, et al., Advanced Materials (Adv. Mater.) Vol. 15, p. 353, 2003
[Problems to be solved by the invention]
The present invention has been made in view of the above-described conventional technology, and without using a template or an expensive catalyst, is inexpensive and can be used for a high-purity light emitting material, a blue-green laser diode, a medium wavelength infrared laser light source, and the like. Manufacturing single-crystal zinc selenide nanowires that are expected to be applied is an issue to be solved.
[0005]
[Means for Solving the Problems]
A mixture of graphite powder and graphite fiber is placed in a first graphite reaction vessel having a hole in the bottom, and zinc selenide powder is placed in a second graphite reaction vessel having a hole in the bottom. In the center of the high-frequency induction heating furnace, the second container is held above the first container by a graphite support surrounded by graphite fiber, and contains water vapor generated by blowing nitrogen gas into distilled water. A nitrogen gas stream is introduced into the first container through a hole in the bottom of the first container and then into the second container through a hole in the bottom of the second container ; The powder and graphite fiber mixture is heated to 1500-1700 ° C and the zinc selenide powder is heated to 1200-1300 ° C. After continuing the heating for 1 to 3 hours, when the reaction vessel is cooled to room temperature, a yellow powder as a product is obtained on the surface of the graphite fiber of the heat insulating material .
[0006]
The graphite powder and the graphite fiber are heated to 1500 to 1700 ° C. in a mixed gas stream of nitrogen gas and water vapor generated by blowing nitrogen gas into distilled water. Nitrogen gas is a carrier gas of water vapor that reacts with graphite. The reason for mixing graphite powder and graphite fiber is to improve contact with water vapor in a fluidized bed.
[0007]
On the other hand, zinc selenide powder as another raw material is heated to 1200 to 1300 ° C. The heating temperatures of the graphite powder, graphite fiber, and zinc selenide powder are each preferably in the above ranges. Even if the temperature is raised to a temperature higher than this, the reaction rate is not improved so much, and when the temperature is lower than this, the reaction is insufficient and the production of the reactive gas and the final product cannot be sufficiently obtained.
The reaction time is preferably 1 to 3 hours, and even if the time is extended beyond this, no improvement in the amount of production can be expected, and if the time is less than this, the reaction is insufficient.
[0008]
The weight ratio of graphite powder, graphite fiber, and zinc selenide powder is preferably about 1: 1: 0.5. Even if this ratio is changed, an improvement in yield cannot be expected.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 conceptually shows a vertical high-frequency induction furnace used to carry out the method of the present invention.
The graphite crucibles 4A and 4B are set apart from each other as a first reaction vessel and a second reaction vessel in a vertical high frequency induction heating furnace 3 in which a heating coil 2 is arranged around the quartz tube 1. The graphite crucibles 4A and 4B are held at the center of the heating furnace 3 by a graphite support (susceptor) 5 surrounded by graphite fibers 6 as a heat insulating material. The mixed graphite powder and fiber 7 are put into the bottom of a graphite crucible 4A having a hole at the bottom, and the zinc selenide powder 9 is put into a graphite crucible 4B having a hole at the bottom.
[0010]
Next, a nitrogen gas stream containing water vapor generated by blowing nitrogen gas into distilled water is introduced from the N ₂ + H ₂ O inlet 10 and introduced into the crucible 4A from the bottom hole, and the mixed graphite powder and Leads to fiber 7. The flow rate at this time is about 1.5 L / min for nitrogen gas and about 0.3 L / min for water vapor. Nitrogen gas may be supplementarily supplied into the quartz tube 1 from the upper N ₂ inlet 11. The water vapor reacts with the graphite mixed with the powder and the fiber, enters the crucible 4B through the hole at the bottom, and reacts with the zinc selenide powder.
[0011]
At this time, using the heating coil 2, the graphite powder and the fiber 7 are heated to 1500 to 1700 ° C. and the zinc selenide powder 9 is heated to 1200 to 1300 ° C. using Gradient. The temperature in the crucibles 4A and 4B is measured by the pyrometer 14 via the prism 13.
[0012]
The reaction gas flows into the quartz tube 1 from above the crucible 4B, and the nitrogen gas is discharged from the N ₂ discharge port 12. After heating for 1 to 3 hours, the furnace is cooled to room temperature. The above reaction is performed in a high frequency induction heating furnace, but the product is deposited on the surface of the graphite fiber 6.
[0013]
【Example】
Next, the present invention will be described in more detail with reference to examples.
Example 1
Using a vertical high-frequency induction heating furnace as shown in FIG. 1, a mixture of 1.0 g of graphite powder manufactured by Wako Pure Chemical Industries, Ltd. and 1.0 g of graphite fiber manufactured by the same company is placed in a graphite crucible and made of graphite. And installed in a high-frequency induction heating furnace. On the other hand, 0.5 g of zinc selenide powder manufactured by Wako Pure Chemical Industries, Ltd. was placed in a graphite crucible and placed above the crucible containing graphite powder and graphite fibers.
[0014]
By blowing nitrogen gas into distilled water, the nitrogen gas containing water vapor generated was passed through the graphite powder and graphite fiber at a flow rate of 1.5 L / min. Using a high frequency induction heating furnace, the graphite powder and the graphite fiber were heated to 1600 ° C., and the zinc selenide powder was heated to 1250 ° C. After heating at this temperature for 2 hours, the heating furnace was cooled to room temperature. A yellow powder was deposited on the surface of the graphite fiber of the heat insulating material outside the graphite crucible.
[0015]
FIG. 2 shows a photograph of the product observed using a transmission electron microscope. As a result, it was confirmed that nanowires having a length of 1 micrometer and an average diameter of 40 nanometers were generated.
[0016]
FIG. 3 shows the measurement result of the X-ray energy diffusion spectrum. It was found that the chemical composition was composed of zinc and selenium, and the atomic ratio was 1: 1. Moreover, it turned out that it is a hexagonal phase which has a lattice constant a = 0.40nm and c = 0.65nm from the high-resolution transmission electron microscope image of this nanowire, and the measurement result of electron beam diffraction. The distances between the (110) plane and the (002) plane were 0.20 nm and 0.33 nm, respectively, and the growth direction of the zinc selenide nanowire was the [001] direction, confirming a single crystal structure. .
[0017]
The photoluminescence spectrum of the generated zinc selenide nanowires was measured at room temperature using a 325 nm He-Cd laser as the excitation source. The results are shown in FIG. From FIG. 4, it was found that the zinc selenide nanowires showed strong orange emission at 617 nm and very weak emission at 447 nm.
[0018]
【The invention's effect】
According to the present invention, zinc selenide nanowires expected to be applied to luminescent materials, medium wavelength infrared lasers, and the like can be produced by a simple method.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a reaction apparatus used for carrying out the method of the present invention.
FIG. 2 is a transmission electron micrograph image of the zinc selenide nanowire obtained in Example 1 instead of a drawing.
3 is a diagram of an X-ray energy diffusion spectrum of zinc selenide nanowires obtained in Example 1. FIG.
4 is a diagram of a photoluminescence spectrum of the zinc selenide nanowire obtained in Example 1. FIG.

Claims (1)

Put a mixture of graphite powder and graphite fiber into a first graphite reaction vessel with a hole in the bottom, and put zinc selenide powder into a second graphite reaction vessel with a hole in the bottom,
The second container is held above the first container at the center of the high-frequency induction heating furnace by a graphite support base surrounded by graphite fiber as a heat insulating material,
A nitrogen gas stream containing water vapor generated by blowing nitrogen gas into distilled water is introduced into the first container from the hole at the bottom of the first container, and then from the hole at the bottom of the second container. Introducing into the second container;
The mixture 1 500-1,700 ° C. of the graphite powder and graphite fiber, a zinc selenide powder 1200 to 1300 ° C., and heated for 1 to 3 hours, depositing the product on the surface of the graphite fibers of the heat insulating material Rukoto A method for producing a single crystal zinc selenide nanowire characterized by

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