JP2004339020A - Method for manufacturing gallium nitride nanotube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing gallium nitride nanotubes which are expected to be applied in a full color flat display, a device for high electric power, a blue color oscillation laser and the field of optical communications. <P>SOLUTION: After heating gallium trioxide to 1,200-1,300 °C in the stream of gaseous nitrogen, the gaseous nitrogen is switched to gaseous ammonia, and the gallium trioxide is heated to 1,350-1,450 °C in the stream of the gaseous ammonia. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention of this application relates to a method for producing gallium nitride nanotubes. More specifically, the invention of this application relates to the production of gallium nitride nanotubes that can produce gallium nitride nanotubes expected to be applied to the field of full-color flat displays, high power devices, blue oscillation lasers, and optical communication fields. It is about the method.
[0002]
[Prior art]
Gallium nitride (GaN) is a semiconductor having a band gap of 3.39 eV, and is a material that emits blue light or ultraviolet light. For this reason, gallium nitride is expected to be applied to full-color flat displays, high-power devices, blue oscillation lasers, and optical communication fields. Such gallium nitride nanowires or nanorods can be obtained by a synthesis method using a template (for example, see Non-Patent Document 1), a laser heating method using a metal catalyst (for example, see Non-Patent Document 2), a hot filament gas. It is manufactured by a phase-liquid-solid growth method (for example, see Non-Patent Document 3), a reaction between gallium oxide and ammonia (for example, see Non-Patent Document 4), and the like.
[0003]
[Non-patent document 1]
W. Q. Hann et al., Science, 1997, Vol. 277, p. 1287
[Non-patent document 2]
X. F. Duan et al., Journal of American Chemical Society (J. Am. Chem. Soc.), 2000, Vol. 122, p. 188
[Non-Patent Document 3]
X. Y. Peng et al., Chemical Physics Letters (Chem. Phys. Lett.), 2000, Vol. 327, p. 263
[Non-patent document 4]
C. C. Chen et al., Advanced Materials (Adv. Mater.), 2000, Vol. 12, p. 738
[0004]
[Problems to be solved by the invention]
However, a gallium nitride nanotube having a hollow inside has not yet been manufactured.
[0005]
The invention of this application has been made in view of such circumstances, and an object of the present invention is to provide a method for producing gallium nitride nanotubes, which can produce gallium nitride nanotubes.
[0006]
[Means for Solving the Problems]
The invention of this application solves the above-mentioned problems by heating gallium trioxide to 1200 to 1300 ° C. in a nitrogen gas stream, then switching the nitrogen gas to ammonia gas, and 1350 to 1450 ° C. in an ammonia gas stream. And a method for producing gallium nitride nanotubes (claim 1).
[0007]
Hereinafter, examples are shown, and the method for producing gallium nitride nanotubes of the present invention will be described in more detail.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In the method for producing gallium nitride nanotubes according to the invention of the present application, as described above, after gallium trioxide is heated to 1200 to 1300 ° C. in a nitrogen gas stream, the nitrogen gas is switched to ammonia gas, and the gallium trioxide is heated to 1350 to 1350 ° C. in an ammonia gas stream. Heat to 1450 ° C. As a result, gallium nitride nanotubes having a uniform outer diameter, inner diameter, and thickness can be obtained.
[0009]
【Example】
In a transparent vertical quartz tube having a length of 50 cm, an outer diameter of 12 cm, and a thickness of 0.25 cm, a graphite cylinder for induction heating having a length of 25 cm, an outer diameter of 4.5 cm, and an inner diameter of 3.5 cm was arranged. . The cylinder is covered with a heat insulating material made of carbon fiber, and a gas introduction pipe and a gas discharge pipe are attached. A graphite crucible having an outer diameter of 2.5 cm, a wall thickness of 3 mm, and a height of 2 cm was placed at the center of the cylinder, and 2.0 g of gallium trioxide (Ga ₂ O ₃ ) powder (purity 99.9) was placed in the crucible. %).
[0010]
Gallium trioxide was heated to 1250 ° C. while flowing nitrogen gas at a flow rate of 80 sccm through the quartz tube, and kept at this temperature for 1.5 hours. Then, instead of nitrogen gas, ammonia gas was flowed at the same flow rate and heated at 1400 ° C. for 1 hour. After completion of the heating, the mixture was cooled to room temperature, and a gray-black product deposited on the carbon fiber heat insulating material was collected.
[0011]
As a result of examining the X-ray diffraction pattern of the product, it was confirmed that the product was gallium nitride having a hexagonal wurtz-type structure with lattice constants a = 3.185 ° and c = 5.177 °. A representative transmission electron microscope image of the product is shown in FIG. Since the outside was dark and the inside was bright, it was confirmed that a hollow portion was present and the structure was a nanotube. The nanotubes ranged in length from a few micrometers to tens of micrometers and had a uniform outer diameter, inner diameter, and wall thickness. A typical nanotube had an outer diameter of 50 nanometers and a wall thickness of 15 nanometers. About 80% of the nanotubes had a linear shape with an open end, and most were polycrystalline.
[0012]
On the other hand, as a result of observing a part of the wall surface of the nanotube having a small amount and having a closed tip with a high-resolution transmission electron microscope, a lattice image showing a single crystal structure was obtained. This had an inter-plane distance of 0.16 nanometers. Further examination by electron diffraction revealed that the crystals were nano-sized microcrystals and were not perfectly aligned.
[0013]
FIG. 2 shows the X-ray energy diffusion spectrum of the nanotube. It was confirmed that the atomic ratio of gallium to nitrogen was 1: 1.10. And the composition was GaN. The signal of Cu in the spectrum is derived from the copper grid of the transmission electron microscope. Also, the O signal is derived from O in the oxidized thin layer of GaO _x outside the gallium nitride nanotube.
[0014]
Of course, the invention of this application is not limited by the above embodiments and examples. It goes without saying that various aspects are possible for details such as the configuration and structure of the apparatus used for the production of gallium nitride nanotubes, and various conditions of the flow rates of nitrogen gas and ammonia gas.
[0015]
【The invention's effect】
As described in detail above, according to the invention of this application, a gallium nitride nanotube expected to be applied to a full-color flat display, a device for high power, a blue oscillation laser, and an optical communication field is manufactured.
[Brief description of the drawings]
FIG. 1 is a high magnification transmission electron microscope image of a product obtained in an example.
FIG. 2 is an X-ray energy diffusion spectrum of a product obtained in an example.

Claims (1)

A method for producing gallium nitride nanotubes, comprising heating gallium trioxide to 1200 to 1300 ° C. in a nitrogen gas stream, switching the nitrogen gas to ammonia gas, and heating to 1350 to 1450 ° C. in the ammonia gas stream.

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