KR20000072642A - Manufacturing technology of gallium nitride powder using transition metal catalyst - Google Patents

Abstract

PURPOSE: A preparation of gallium nitride(GaN) powder using transition metal catalyst is provided, which has improved crystallinity increased reaction rate and high yield. CONSTITUTION: The preparation of gallium nitride(GaN) is characterized in that a powder or net-typed transition metal catalyst such as Ni, Co, Pt and Pd is used in a conventional GaN powder produced from gallium and ammonia in a temperature of 900-1200°C, followed by extracting and refining with an inorganic acid such as HCl, HNO3 and H2SO4.

Description

Manufacturing technology of gallium nitride powder using transition metal catalyst {.}

The present invention relates to the production of gallium nitride (GaN) powder, which has been attempted at home and abroad using a transition metal as a catalyst.

The production of conventional gallium nitride powder 1) In 1984, S Porowski et al prepared gallium nitride powder by reacting gallium and ammonia in a high pressure reactor. Although gallium nitride powder is manufactured at a relatively low temperature, it has disadvantages in that it requires a high pressure in manufacturing and a manufacturing time requires a longer time than other methods. "J. Karpinski, J. Jun, S. Porowski, J. Crystal Growth, 66, 11 (1984)"

2) The preparation of gallium nitride powder using precursors was carried out at low temperature and low pressure by Jerzy F. Janik et al. In 1996, but it is not easy to prepare unstable precursors at room temperature. Requires working in a vacuum. This requires a multi-step process and requires careful attention. "Jerzy F. Janik, Chem. Mater., 8, 2708 (1996)"

3) The direct reaction method used to produce gallium nitride powder, which is used as a raw material for thin gallium nitride, was first manufactured by Juza and Hahn in 1940. However, it has a disadvantage of requiring a high production temperature and a long production time. "R.Juza and H. Hahn, Anorg, Allgem. Chem., 234, 244 (1940)"

4) The method of blowing ammonia gas into the liquid gallium to form ammonia gas droplets and producing gallium nitride in the liquid is considered suitable for producing gallium nitride at a relatively low temperature and for mass production and industrialization of the device. However, this method requires a long production time.

The present invention proposes a new method of preparing gallium nitride using a catalyst that supplements the problems raised in the manufacturing process of gallium nitride powder reported so far. The present invention aims to obtain a higher yield, faster production speed, and higher quality gallium nitride powder by incorporating a transition metal catalyst into the reaction of the conventional method for producing gallium nitride powder in gallium liquid by supplying ammonia gas to the gallium liquid. Leave.

Figure 1 (A) of gallium nitride prepared by the present invention Direction and (B) Transmission electron diffraction (TED) pattern photograph in the direction.

2 is an optical luminisense (PL) spectrum of gallium nitride prepared by the present invention.

3 is an electron microscope (SEM) photograph of gallium nitride prepared according to the present invention, in which (a) catalyst is not used and (b) Ni catalyst is used.

[Description of the Code]

In order to achieve the above object, the present invention proposes a new method for preparing gallium nitride powder by introducing a catalyst into a gallium liquid in which gallium and ammonia are directly reacted.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Conventional gallium nitride was prepared by using a method of blowing ammonia gas into a gallium liquid during the reaction. The present invention provides a method of activating the reaction of ammonia and gallium by using a potential metal catalyst to promote gallium nitride production. In other words, by introducing a catalyst into the conventional method for producing gallium nitride, it is possible to accelerate the decomposition of the gas to be supplied and to activate the production reaction on the surface of the catalyst, thereby reducing the reaction time and improving the crystallinity of gallium nitride and increasing the yield. .

Example 1

1 wt% or less of nickel (Ni) catalyst is installed in the reactor, and gallium (8 g) is added thereto. After the reactor was installed in an electric furnace, nitrogen was flowed to adjust the pressure in the reactor to atmospheric pressure. When the pressure of the reactor is at atmospheric pressure, the hydrogen gas is supplied up to 800 ° C. instead of nitrogen gas, the feed gas is converted to ammonia, and the powder of gallium nitride is prepared at the reaction temperature.

The preparation of gallium nitride was carried out at 1100 ° C. The gallium nitride prepared was separated from the unreacted material by using an acid. The product (GaN), which does not react with acid, was extracted, washed with distilled water, separated using a filter, and dried in a vacuum oven. Hydrochloric acid (HCl) was used to purify the unreacted gallium and gallium nitride.

Example 2

The gallium (8g) and cobalt (Co) catalyst was put together in the reactor and the reactor was installed in an electric furnace and the reaction was carried out in the same manner as in Example 1.

Example 3

The gallium (8g) and platinum (Pt) catalyst was put together in the reactor and the reactor was installed in an electric furnace, and the reaction was performed in the same manner as in Example 1.

Example 4

The gallium (8g) and palladium (Pd) catalyst was put together in the reactor, the reactor was installed in an electric furnace and the reaction was carried out in the same manner as in Example 1.

[Comparative Example]

In order to compare with the prior art, only gallium (8 g) was added to the reactor without introducing a catalyst, and the reactor was installed in an electric furnace.

Table 1 Comparison of production rates of gallium nitride with temperature in the presence of a catalyst.

As can be seen from the results in Table 1, the production rate of Example 1 in which gallium nitride was prepared using a nickel catalyst was doubled at 1000 ° C. and 5 times at 1050 ° C., at 1100 ° C., compared to the production rate of the comparative example prepared in the prior art. At 9 times 1150 ℃, it increased rapidly as the temperature increased 10 times. The catalytic effects observed in Example 1 were also obtained in Examples 2, 3, and 4 using other potential metal catalysts. As the reaction temperature increased, the production rate rapidly increased and the reaction time also decreased drastically.

In order to investigate the structure and optical properties of the sample produced in Table 1, the transmission electron diffraction (TED) pattern and the light luminisense (PL) spectrum were measured, respectively. All samples showed typical transmission electron diffraction pattern and photoluminescence spectra of gallium nitride. As a result of confirming the size of the sample by using an electron microscope (SEM), in the case of Example 1, Example 2, Example 3, and Example 4 using the catalyst particles having a size more than twice the size of the comparative example without the catalyst Seemed to be prepared.

This is because the catalyst reduces the production activation energy of gallium nitride to increase the reaction rate, and at the same time promotes the thermal decomposition of the supplied ammonia. As the ammonia gas injected into the liquid gallium through the delivery tube passes between the catalysts, the decomposition process is accelerated, and the decomposed ammonia ions and the gallium liquid are accelerated by the catalyst. Decomposition of the gas supplied from the surface of the catalyst and the manufacturing process of gallium nitride are performed together, and the chemical reaction takes place along the reaction path with low activation energy, thereby reducing the reaction time and improving the selectivity of the desired product. Improved crystallinity and yield of gallium powder can be greatly increased.

As a result of preparing gallium nitride using the catalysts identified in the examples in Table 1, it was found that the amount of gallium nitride produced increased rapidly, and the particle size was increased.

By using the catalyst as described above, it is possible to reduce the activation energy of the synthesis to increase the production rate, thereby increasing the yield of the product. The initial catalyst provides a nucleation site and increases the size of the gallium nitride powder. In addition, the catalyst promotes decomposition of ammonia during the pyrolysis of the ammonia to be supplied, thereby increasing the supersaturation of the gas to be supplied, thereby improving the crystallinity of the gallium nitride powder.

Claims (4)

A method of producing gallium nitride using gallium and ammonia, the method of producing gallium nitride powder using a transition metal as a catalyst, and then extracting and purifying with an inorganic acid. The method of claim 1, wherein the transition metal catalyst is one of nickel (Ni), cobalt (Co), platinum (Pt), and palladium (Pd). The method according to claim 1 or 2, wherein the preparation of gallium nitride is carried out at a temperature range of 900 to 1,200 ° C. The process according to claim 1, wherein the inorganic acid uses one of hydrochloric acid (HCl), nitric acid (HNO ₃ ), sulfuric acid (H ₂ SO ₄ ).