KR100826305B1 - The fabrication method of needle like single crystalline aln nanorod - Google Patents

Abstract

A method for manufacturing a needle type single crystalline AlN nano-rod is provided to enhance efficiency and to extend a lifetime of the needle type single crystalline AlN nano-rod. An aluminum metal, a hydrochloric gas, and an ammonia gas react under nitrogen gas atmosphere during 10-30 minutes at temperature of 680-720 °C. Aluminum metal powders are positioned in the inside of the quartz tube. The hydrochloric gas/nitrogen is introduced into the inside of the quartz tube. The ammonia gas/nitrogen is introduced into the inside of the quartz tube. In the introduced gas, a volume ratio of HCl/NH3 is 0.02 to 0.05 and a volume ratio of (HCl/N2)/(NH3/N2) is 0.6 to 0.8. The total flow rate of the introduced gas corresponds to a range of 600 to 1000 sccm. A single crystalline nano-rod(110) is formed by introducing the gas in the flow rate.

Description

The fabrication method of needle like single crystalline AlN nanorod}

1 shows a schematic view of an aluminum nitride single crystal nanorod grown vertically by chloride vapor phase epitaxial method on a silicon substrate according to the present invention.

Figure 2 shows a schematic diagram of a chloride vapor phase epitaxial growth apparatus for producing aluminum nitride single crystal nanorods according to the present invention.

3 illustrates a method of fabricating a field emission device using aluminum nitride single crystal nanorods grown vertically on a silicon substrate according to the present invention.

[Description of Reference Symbols for Main Parts of FIGS. 1, 2, and 3]

110; Growth controlled aluminum nitride nanorods 120; Board

310; Al metal powder 321; HCl: N ₂ gas inlet 322; NH ₃ : N ₂ gas inlet

340; Interior quartz tube 350; Reaction Quartz

411a; Top plate quartz glass 412b; Lower plated quartz glass 421a and 422b; ITO transparent electrode layer

430; Phosphor coating layer 440; Insulation pillar

Figure 4 shows a scanning electron microscope (SEM) of the aluminum nitride nanorods prepared according to the present invention, (A) low magnification (× 12K), (B) high magnification (× 40K) of the needle-like structure is shown. .

Figure 5 shows the XRD of the aluminum nitride nanorods prepared in accordance with the present invention.

6 shows a transmission electron microscope (TEM) photograph of the needle-shaped aluminum nitride nanorod manufactured according to the present invention, (A) low magnification (× 300K), and (B) high magnification (× 500K).

Figure 7 shows a graph measuring the field emission of the field emission device manufactured using the needle-shaped aluminum nitride single crystal nanorod prepared according to the present invention.

8 is a scanning electron microscope (SEM) photograph of the aluminum nitride single crystal nanorods prepared in Comparative Examples 1 to 4, and Comparative Example 1 (A), Comparative Example 2 (B), Comparative Example 3 (C) and Comparative Example 4 (D) is shown.

9 is a scanning electron microscope (SEM) photograph of the aluminum nitride single crystal nanorod manufactured in Comparative Example 5, and shows 0.5 inches (A) and 1.5 inches (B).

The present invention relates to a method for producing an aluminum nitride single crystal nanorod having a needle-like structure, and more particularly, aluminum chloride by reacting aluminum (Al) metal powder and hydrogen chloride (HCl) gas in a nitrogen (N ₂ ) gas atmosphere. When the chloride gas phase epitaxial method is performed to form (AlCl _x ) gas and simultaneously react with the AlCl _x gas and ammonia (NH ₃ ) gas to form AlN, reaction conditions such as temperature and time, hydrogen chloride gas (HCl) and By adjusting the partial pressure of ammonia gas (NH ₃ ) and the position of the aluminum metal powder and the substrate to a specific range, it has a high density uniform single crystal and a needle-like structure, which is a next-generation display and nano photonic, especially a field emission display device. The present invention relates to a method for producing an aluminum nitride single crystal nanorod having a needle-shaped structure usefully used in emitters.

Currently, various flat panel displays such as liquid crystal display (LCD), plasma display panel (PDP), field emission display (FED), and electroluminescence (EL) are developed and put into practical use. It is becoming.

Among them, FED, which is relatively recently proposed, has the same light emitting mechanism as Cathode Ray Tube (CRT) and emits light by collision of electrons and phosphors emitted in vacuum, and has a shape of several mm in shape. . As a result, the FED has the advantages of CRT, such as high resolution and full color, but it is light and thin, and thus has low power consumption. In particular, FED has excellent characteristics in terms of viewing angle and environmental resistance, which are disadvantages of thin film transistor (TFT) LCDs, and is potentially attractive, but it is difficult to manufacture field emission emitters having high brightness, low power, and long emission lifetime. The disadvantage is that it is very difficult.

The electron emission emitter includes a spin type emitter having a sharp tip that emits electrons by forming an electric field due to a voltage difference applied to the cathode electrode and the gate electrode, and a voltage difference applied to the cathode electrode and the anode electrode. There is a plane type emitter that emits electrons by electric field formation.

The emission characteristics of the field emission tip are greatly influenced by negative electron affinity. The smaller the electron affinity, the lower the voltage required for electron emission. If the electron affinity is negative, electrons are spontaneously released from the tip until the field emission is stopped by space charge. At this time, the space charging can be overcome by applying a small voltage of several volts.

Molybdenum (Mo), graphite / diamond-like carbon (Diamond Like Carbon, DLC), carbon nanotubes (CNT), and silicon (Si) have been suggested as materials for field emission tips, but the spin type Difficult to manufacture Specifically, for example, when silicon is used, it is advantageous because it is compatible with the existing integrated circuit (IC) process and the driving circuit can be built in. However, silicon has a low electric field because of its large work function and easy oxidation. It exhibits emission efficiency and is unstable thermally or mechanically, causing unstable fluctuations in current when it emits electric field for a long time. In addition, thin-film emitters such as diamond or diamond-like carbon require high-stable manufacturing conditions such as the synthesis of emitter-forming materials each time the display is manufactured and the manufacturing conditions must be kept constant. It is not easy and has disadvantages such as high production cost due to disadvantage in mass production.

In order to overcome these disadvantages, it is urgently required to coat silicon emitters with Mo, DLC, diamond, etc., which have excellent thermal conductivity and have a low work function, or to develop new emitter materials.

As described above, the field emission emitter should satisfy requirements such as excellent chemical and mechanical stability as well as low electron affinity. However, it is not easy to manufacture a field emission emitter that meets these requirements.

Accordingly, the present inventors are one of Group III nitride (III-Nitride) based materials that meet the requirements of the field emission emitter and are attracting attention as a next-generation material, and have a wide bandgap energy in the range of about 6.2 eV. A method for producing aluminum nitride having a particularly acicular structure among aluminum nitride (AlN) having excellent thermal conductivity and strength, excellent chemical stability and high melting point, by using an improved chloride gas phase epitaxial method is proposed.

Specifically, by using a specific chloride gas phase epitaxial method apparatus, aluminum (Al) metal powder and hydrogen chloride (HCl) gas is reacted in a nitrogen (N ₂ ) gas atmosphere to form aluminum chloride (AlCl _x ) gas at the same time. Chloride gas phase epitaxial method of reacting with AlCl _x gas and ammonia (NH ₃ ) gas to form AlN, the reaction temperature, partial pressure of hydrogen chloride gas (HCl) and ammonia gas (NH ₃ ), and location of aluminum metal powder and substrate By adjusting to a specific range, it was found that aluminum nitride (AlN) nanorods having a needle-like structure while having a high density and uniform single crystal were formed, thereby completing the present invention.

Accordingly, the present invention provides a method for producing an aluminum nitride single crystal nanorod having a needle-like structure by performing a chloride vapor phase epitaxial method (HVPE) by adjusting a specific apparatus, reaction temperature and partial pressures of hydrogen chloride gas and ammonia gas to a specific range. The purpose is to provide.

In the present invention, in the reaction quartz tube 350, the substrate 120, the aluminum metal powder 310, the hydrogen chloride gas / nitrogen injection portion 321, the ammonia gas / nitrogen injection portion 322, and the internal quartz tube 340 are formed. Using the configured device,

Under a nitrogen stream, aluminum metal, hydrogen chloride gas and ammonia gas are simultaneously reacted at 680 to 720 ° C. for 10 to 30 minutes, wherein an aluminum metal powder is positioned inside the inner quartz tube 340, and the hydrogen chloride gas / nitrogen is internal quartz. It is introduced into the tube 340, ammonia gas / nitrogen is introduced into the reaction quartz tube 350, the volume ratio of the introduced gas is HCl / NH ₃ is introduced in a 0.02 ~ 0.05 volume ratio, (HCl / N ₂ ) / (NH ₃ / N ₂ ) is characterized in that the needle-shaped aluminum nitride single crystal nanorods are introduced in a volume ratio of 0.6 to 0.8 to form single crystal nanorods.

Hereinafter, the present invention will be described in detail.

The present invention performs a chloride vapor phase epitaxial method (HVPE) using a specific apparatus and controls reaction conditions such as partial pressure of hydrogen chloride gas and ammonia gas and reaction temperature and time to a specific range, as shown in FIG. A tip portion has a diameter of 20 to 50 nm, a length of about 1 to 2 μm, and a method for producing a needle-shaped aluminum nitride single crystal nanorod that grows vertically at a high density.

In the related art, Korean Patent Registration No. 623271 has proposed a method for manufacturing a single crystal gallium manganese nitride nanowire having a controlled doping amount of manganese metal by adjusting the amount of hydrogen chloride gas and ammonia gas in a specific range. The invention presented above is to control the amount of hydrogen chloride gas and ammonia gas to control the doping amount of the manganese metal doped in the gallium metal so that there is no internal defect, the gallium manganese nitride nanowires prepared in the columnar (columnar) There is a difference in the structure of the nanorods from the needle-shaped of the present invention.

That is, in the present invention, the nanorod manufactured by using aluminum metal alone has a needle structure, and is a high-density uniform monocrystalline aluminum nitride (AlN) nanorod, compared with the above-described conventional technique. Although similar in terms of the use of the Shirrel method, the present invention is characterized by the technical constitution in that the reaction conditions such as the reaction apparatus, partial pressure and temperature of the gas used, growth time and the like are specifically defined to form a needle shape.

In general, in the case of the pointed needle type in the field emission device, the critical driving voltage capable of emitting an electric field is very excellent in emitting electrons at a lower driving voltage than the columnar type, and in particular, the field emission emitter It is very suitable for use. However, despite this usefulness, the production of nanorods having a needle-like structure has never been easy, and thus its use has been limited.

For reference, the chloride vapor phase epitaxial method used in the present invention is similar to the conventional halide vapor phase epitaxial method (HVPE), and the reaction is performed by using chloride instead of the halide.

Hereinafter, a method of manufacturing the acicular aluminum nitride single crystal nanorod according to the present invention will be described in detail.

When synthesizing aluminum nitride (AlN) single crystal nanorods through HVPE system, reactants such as aluminum (Al) metal powder, hydrogen chloride (HCl) gas and ammonia (NH ₃ ) gas are thermally decomposed and reacted with aluminum nitride on the substrate. (AlN) is formed, and the reaction thereof is the same as in Scheme 1 and Scheme 2.

Scheme 1

Al (s) + 3HCl (g) → AlCl ₃ (g) + 3 / 2H ₂ (g)

Scheme 2

AlCl ₃ (g) + NH ₃ (g) → AlN (s) + 3HCl (g)

As shown in Schemes 1 and 2, Al solid powder reacts with HCl gas to form AlCl ₃ chloride, and then reacts with NH ₃ gas to prepare AlN single crystal nanorods. At this time, when continuously injecting HCl and NH ₃ gas, since the partial pressure of AlCl ₃ and NH ₃ rises, Scheme 2 occurs faster toward the forward reaction, and more AlN can be deposited on the substrate. In other words, it is possible to control the amount of AlN using HCl and NH ₃ . However, N ₂ gas plays a role of carrier and dilute of the reaction gas (HCl, NH ₃ ) and controls the partial pressure of the premises, and does not directly affect the reaction.

That is, the present invention reacts with Al metal powder, HCl gas and NH ₃ gas at a specific temperature using the apparatus shown in FIG. 2 to produce a single crystal AlN nanorod on the substrate as shown in FIG. At this time, HCl: N ₂ gas for making Al solid powder into chloride and NH ₃ : N ₂ gas to react with chloride are controlled at a specific ratio, and the position and reaction conditions of Al metal powder and substrate are controlled, and the needle type The technical features of the aluminum nitride single crystal nanorods are as follows.

A method of manufacturing acicular aluminum nitride single crystal nanorods using the HVPE system schematic of FIG. 2 will be described in detail as follows.

It consists of a horizontal tube furnace and a reaction quartz tube 350 in the form of a tube and an internal quartz tube and a gas input line, and injects HCl: N ₂ gas into the internal quartz tube 340 (321), and simultaneously NH ₃ : N ₂ gas is injected (322). The length of the inner quartz tube 340 is preferably 40 to 60% by length, preferably about 50% by weight with respect to the reaction quartz tube 350, the diameter of the inner quartz tube with respect to the inner diameter of the reaction quartz tube It is maintained in the range of 2-3% by length, preferably 2.5-3% by length. The range is called a 'hot zone (HOT ZONE)', and the aluminum metal powder 310 is located in the inner quartz tube 340 as the portion where the temperature is maintained to be the highest during the reaction. Therefore, the aluminum metal powder 310 is preferably located in a hot zone temperature, which is located in a range of 3 to 10 length% of the total quartz tube length based on the exit of the internal quartz tube 340. It is desirable to.

In addition, the needle-shaped single crystal nanorod according to the present invention is formed in the exit direction from the contact surface contacting the substrate and the exit of the internal quartz tube 340, the portion in which the nanorod is formed in the exit direction based on the contact surface It is formed in the range of 1/3 to 2/3 with respect to the substrate length. Within the 1/3 range, since nucleation and particle growth occur at the initial stage of deposition depending on the deposition distance, nanorods are not formed and the particles are densely packed together to form agglomerates. Due to the high deposition rate, the deposition rate decreases rapidly, and small lumps are rarely formed.

The nitrogen is used as a carrier gas and a dilute gas, and the actual reaction uses hydrogen chloride gas and ammonia gas.

The total flow rate of the incoming gas used for the reaction, that is, nitrogen, hydrogen chloride gas and ammonia gas, is injected in the range of 600 to 1000 sccm, preferably in the range of 650 to 750 sccm, if the flow rate is less than 600 sccm on the substrate. When a thick thin film of aluminum chloride is formed and exceeds 1000 sccm, a rod having a columnar shape having a large particle diameter and a short length is formed, which is not suitable for the above purpose.

The hydrogen chloride gas and the ammonia gas are injected at a [HCl / NH ₃ ] gas flow rate of 0.02 to 0.05 volume ratio, preferably 0.02 to 0.03 volume ratio. If the injection amount is less than 0.02 volume ratio, AlCl _x and NH ₃ gas, which is a raw material gas of AlN, is used. As the amount of is reduced, small particles are formed without forming single crystal nanorods, and when the volume ratio exceeds 0.05 volume ratio, the amount of raw material gas is rapidly increased to form a thick buffer layer, and a short and thick rod is formed thereon. It is preferable to maintain the above range because a problem arises due to different thermal expansion of the substrate during cooling.

In addition, the hydrogen chloride gas and the ammonia gas, that is, [hydrogen chloride gas / nitrogen] / [ammonia gas / nitrogen] are injected at a volume ratio of 0.6 to 0.8, and when the injection amount is less than 0.6 volume ratio, the hydrogen chloride gas and the ammonia gas do not have a sufficient deposition ratio. If the particles are formed and exceeds the volume ratio of 0.8, the AlCl _x gas is generated so that the remaining AlCl _x and Cl ₂ solid particles are formed on the surface of the substrate without reacting with ammonia.

This reaction is carried out for 10 to 30 minutes at an atmospheric pressure of 680 ~ 720 ℃, preferably 690 ~ 700 ℃ bar, if the reaction temperature is less than 680 ℃ to form a thin film on the substrate, if it exceeds 720 ℃ short It is desirable to maintain this range because of the problem of coarse columnar structure and formation of many particles. The temperature range is similar to the conventional one, but is carried out in a more specific range to achieve the object of the present invention. In addition, unlike the conventional halide vapor phase epitaxial method is carried out under pressure in the range of 10 ^-2 ~ 10 ^-8 mtorr, the present invention can be carried out at atmospheric pressure, which is moved to the nucleus after the vapor deposition of chloride gas phase by hydrogen chloride This is because the deposition rate increases due to the low activation energy generated and the high vaporization rate of AlCl _x .

In general, the growth time is increased by volume growth rather than length growth, so that the diameter of the nanorod becomes larger, so that it has a shape that is not suitable for use as a FED emitter to maintain a growth time of 10 to 30 minutes in the growth temperature range It is preferable.

The substrate is generally used in the art, but is not particularly limited, and specifically, a silicon wafer, sapphire, GaAs, and SiC wafer substrate may be used. Preferably, a silicon wafer and a silicon carbide wafer are used. The sapphire, GaAs substrate and the like may form a buffer layer of 0.5 to 1 ㎛ may cause unfavorable results in the field emission.

At this time, the substrate is cleaned using a BOE (Buffer Oxide Etcher, 6: 1) to remove the native oxide (hot oxide) in the center (hot zone) in the tube (tube), before the start of the process, to remove residual oxygen Purging for use is good.

As described above, the aluminum nitride single crystal nanorod manufactured according to the present invention has a needle structure, and a high density uniform single crystal aluminum nitride (AlN) nanorod is formed, which is particularly applicable to emitters of field emission display devices. It is chemically and mechanically stable, and has a field emission voltage that is significantly lower than the field emission pressure in the range of 2 to 6 V / µm, compared to the conventional 7 to 24 V / µm range.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not limited by the Examples.

Example

After removing the native oxide by washing the recon wafer substrate having a growth direction of (100) plane and having a width of 6 cm, a length of 0.5 cm, and a height of 0.07 cm with BOE (Buffer Oxide Etcher, 6: 1), the reaction was performed. The quartz tube 350 was placed in a hot zone inside the tube and purged for 30 minutes to remove residual oxygen prior to the start of the process.

As shown in the schematic diagram of the HVPE system of FIG. 2, an internal quartz tube having a 40 cm length and a 0.6 cm inner diameter located in a reaction tube 350 having a horizontal tube path and a tube shape having a 80 cm length and a 28 cm inner diameter ( 340) was injected into HCl: N ₂ (321), and NH ₃ : N ₂ (322) gas was injected into the reaction quartz tube 350. At this time, the aluminum (Al) metal powder is located about 1 inch (inch) from the end of the inner quartz tube into which gas is injected, the outlet of the inner quartz tube 340 is located on the upper surface of the substrate 120, the end of the outlet The edge and the end of the substrate were kept in a straight line. At this time, the temperature was grown for 25 minutes at 700 ℃ to prepare an aluminum nitride single crystal nanorod. Nitrogen, hydrogen chloride gas and ammonia gas, which are the total gases to the reaction quartz tube 350, are 800 sccm, the ratio of [HCl / NH ₃ ] gas flow rate is 0.03, and [HCl / N ₂ ] / [NH ₃ / N ₂ ]. Was 0.7 by volume.

The grown AlN nanorods have a needle-like structure located about 1/3 of an inch with respect to the length of the substrate formed in the exit direction with respect to the contact surface between the substrate and the internal quartz tube.

In addition, in order to measure the field emission characteristics of the grown AlN nanorods, a quartz glass plate coated with ITO is used as shown in FIG. 3, and the upper plate is coated with a phosphor layer for FED on the lower portion to emit electrons of AlN invented. We designed a device structure that can be confirmed.

Next, as shown by the scanning electron microscope of FIGS. 4 (A) and (B), it was confirmed that the grown AlN nanorods showed a vertically oriented needle shape having a uniform diameter and length. In addition, FIG. 5 shows a result obtained by the X-ray diffraction analyzer of the grown single crystal AlN nanorods, and it was confirmed that the grown AlN nanorods had preferential orientation with (002 plane).

Next, Figure 6 is a transmission electron micrograph of the grown nanowires, (A) was confirmed that the needle-like structure of the pointed nano-rod shape, (B) has a single crystal lattice structure without defects. It was confirmed that the surface of the nanowires grew a good quality one-dimensional single crystal AlN nanorod without an oxide layer or an amorphous layer.

Next, FIG. 7 shows a field emission characteristic graph measured using the field emission device of FIG. 3, and it can be seen that the grown AlN nanorods are driven at about 2.6 V / μm.

Comparative Examples 1 to 4

A single crystal AlN nanorod was prepared in the same manner as in Example 1, but with different reaction conditions as shown in Table 1 below.

division Reaction temperature (℃) [HCl / NH ₃ ] (volume ratio) [HCl / N ₂ ] / [NH ₃ / N ₂ ] (volume ratio) Total gas flow rate Comparative Example 1 650 0.03 0.8 750 Comparative Example 2 800 0.03 0.8 750 Comparative Example 3 700 0.03 0.6 1500 Comparative Example 4 700 0.1 0.8 800

As shown in Table 1, when the reaction temperature is outside the scope of the present invention as in Comparative Examples 1 and 2, even if the small particles or columnar nanorods shown in Figs. 8A and 8B are formed, a buffer layer is formed. You can see that it becomes. This is a factor that reduces the field emission effect. That is, it can be seen that the needle-shaped nanorods grown in the specific temperature range are affected by the deposition rate according to the growth temperature.

In addition, when the total gas flow rate is outside the scope of the present invention as in Comparative Example 3, as shown in FIG. 8 (C), the crystal structure of the thick thin film was confirmed, and the columnar thin film structure was formed inside the thin film. Confirmed. This is believed to be due to the increase in the reaction pressure of the reaction tube as well as the nucleation of the reactor as well as the nuclear growth.

Comparative Example 4 is a case in which the ratio of hydrogen chloride to ammonia is outside the scope of the present invention. When the ratio of hydrogen chloride to ammonia is increased, needle-shaped nanorods are formed, but the ratio of AlCl _x reactant is increased by HCl to make it uniform. It could be confirmed that the deposition was not performed and a relatively thick, non-uniform buffer layer was formed.

Comparative Example 5

In the same manner as in Example 1, based on the contact surface of the substrate and the internal quartz tube, the nano-rod formed at the point of 0.5 inches or less and 1.5 inches or more in the exit direction was observed.

Next, as shown in Figs. 9A and 9B, the nanorods are not formed and the particles are densely packed to form agglomerates, or small agglomerates are rarely formed.

As described above, the one-dimensional single crystal AlN nanorod manufactured according to the present invention is advantageously applied as a field emission emitter for FED, by which it is possible to realize a low power, high efficiency and stable long life light emitting device, and not only an FED emitter but also a mechanical Because of its excellent properties, it can be used as a microprobe for MEMS. Especially, since it has a needle-shaped one-dimensional structure, it can be used as a probe tip of AFM or STM. Therefore, it can be applied as UV photo detector and UV laser, and can be used for various fields as well as next-generation display and nano photonic.

Claims (9)

In the reaction quartz tube 350, a device including the substrate 120, the aluminum metal powder 310, the hydrogen chloride gas / nitrogen injection portion 321, the ammonia gas / nitrogen injection portion 322, and the internal quartz tube 340 is provided. using, Under nitrogen stream, aluminum metal, hydrogen chloride gas and ammonia gas were simultaneously reacted at 680-720 ° C. for 10-30 minutes, Aluminum metal powder is located in the inner quartz tube 340, The hydrogen chloride gas / nitrogen is introduced into the inner quartz tube 340, the ammonia gas / nitrogen is introduced into the reaction quartz tube 350, The volume ratio of the introduced gas is HCl / NH ₃ is introduced in a volume ratio of 0.02 ~ 0.05, (HCl / N ₂ ) / (NH ₃ / N ₂ ) is introduced in a volume ratio of 0.6 ~ 0.8, The total flow rate of the introduced gas flows in the range of 600 to 1000 sccm to form single crystal nanorods. The method of claim 1, wherein the length of the inner quartz tube is 40 to 60% by length relative to the reaction quartz tube, the inner diameter of the inner quartz tube is 2 to 3% by length relative to the inner diameter of the reaction quartz tube Method of manufacturing type aluminum nitride single crystal nanorods. delete The aluminum nitride single crystal of claim 1, wherein the aluminum metal powder 310 is located in a range of 3 to 10% by length with respect to the total length of the internal quartz tube based on the exit of the internal quartz tube 340. Method of manufacturing nanorods. The method of claim 1, wherein the prepared aluminum nitride single crystal nanorods have a diameter of 20 to 50 nm, a length of 1 to 2 µm, and a needle shape. 2. The aluminum nitride single crystal of claim 1, wherein the prepared aluminum nitride single crystal nanorods are formed in a range of 1/3 to 2/3 with respect to the length of the substrate in which the substrate and the internal quartz tube are formed in the exit direction with respect to the contact surface. Method of manufacturing nanorods. The method of claim 1, wherein the substrate (120) is a silicon wafer or a silicon carbide wafer. delete delete

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