KR20100113884A

KR20100113884A - Preparing methods of vertical-type light emitting diode comprising zno nanostructures

Info

Publication number: KR20100113884A
Application number: KR1020090032424A
Authority: KR
Inventors: 김상우; 이강혁
Original assignee: 금오공과대학교 산학협력단
Priority date: 2009-04-14
Filing date: 2009-04-14
Publication date: 2010-10-22

Abstract

The present invention relates to a method of manufacturing a vertical light emitting diode including a zinc oxide nanostructure.

The wet method according to the present invention can form a zinc oxide nanostructure on the vertical light emitting diode n-type semiconductor layer even at a low temperature of 200 ° C. or less, and an electrode layer due to heat generated when the nanostructure is formed by a conventional chemical vapor deposition method. No damage occurs. In addition, the present invention has an advantage that can easily control the diameter and length of the nanostructure, it can be usefully used in the field of light emitting diodes.

Description

Preparation method of vertical-type Light Emitting Diode comprising ZnO nanostructures

The present invention relates to a method of manufacturing a vertical light emitting diode including a zinc oxide nanostructure, and relates to an invention capable of increasing light extraction efficiency by forming a zinc oxide nanostructure on top of a vertical light emitting diode at a low temperature.

Elements constituting the efficiency of the light emitting diode device are composed of the efficiency of the light emitting diode chip, the phosphor efficiency, and the package efficiency. Among them, the performance of the light emitting diode chip is determined by the combination of the internal quantum efficiency and the external quantum efficiency.In order to satisfy the required performance according to the expansion of the light emitting diode application market in the future, the internal quantum efficiency of the light emitting diode itself and the external quantum efficiency are improved. Efficiency is inevitably required to improve.

Currently, several advanced companies have already reported internal quantum efficiencies of more than 90% in the low current range. On the other hand, the light extraction efficiency in the chip is quite insufficient. This results in total reflection due to the difference in refractive index at the interface between the device and the air when the light generated in the multi-well structure is emitted out of the device (for GaN, the refractive index is about 2.5 in the visible region, and for air, the refractive index In this case, when light is emitted from gallium nitride into the air, only light coming within a critical angle of 23 degrees can escape. Therefore, in order to overcome these limitations of the light emitting diode, it is necessary to develop a device design and develop a reflective electrode to reduce total reflection.

In order to commercialize a large area / large-capacity light emitting diode, it is not a structure that is grown and manufactured on the current insulating sapphire substrate, but a new structure that is vertical after removing the sapphire substrate using various methods such as laser lift-off. Development of a light emitting diode is absolutely necessary, and there are still high technological advances. However, it still has a low external quantum efficiency due to the large difference in refractive index, which is an optical property of the material.

The light emitting diode electrode can be largely divided into p-type and n-type electrodes. In the case of p-type electrode and n-type electrode, Ni / Au, Ti / Al, etc. have been developed in Nichia and are widely used worldwide. have. However, in order to replace the p-electrode due to the low permeability and thermal characteristics of the metal electrode, researches on the transparent oxide electrode have been actively conducted worldwide, and ITO (Indium Tin Oxide) electrode is almost commercialized. Close, but not enough electrical properties yet. In addition, a high output vertical light emitting diode incorporating an Ag-based p-type reflective electrode has been developed and commercialized.

In the case of the n-electrode, the gallium polar electrode is generally less interested in research than the p-electrode because the titanium or chromium-based form shows superior performance. However, the development of vertical light emitting diodes such as OSRAM is being actively conducted worldwide. . In addition, since vertical light emitting diodes require a nitrogen polarity n-electrode, research on this is being actively conducted.

However, at present, since the development of the vertical light emitting diode is still in the early stage of the nitrogen polar n-electrode, little is known about it. In Korea, research on n-electrodes for vertical light emitting diodes has been actively conducted by companies such as Samsung Electro-Mechanics and LG Innotek.

In particular, n-type gallium nitride has almost no problem in general epi-up chips, but it has revealed a big problem when changing the chip structure to a vertical structure. In the vertical structure, n-type gallium nitride, unlike the epiupe structure, exposes the surface of nitrogen polarity. When an electrode is formed on the surface of the nitrogen polarity, it is thermally unstable. That is, the specific contact resistance of the electrode is significantly increased after the heat treatment. In other words, it is necessary to develop a thermally stable n-type transparent electrode.

Therefore, a technology capable of arranging the zinc oxide nanostructures at a low temperature on the n-type semiconductor layer above the vertical light emitting diodes, and easy to control the shape of the nanostructures, the technology for forming the structure is not limited It is required.

Disclosure of Invention The present invention is to solve the above-described problems, while forming a zinc oxide nanostructure on the n-type semiconductor layer of the vertical light emitting diode at low temperature conditions, manufacturing a vertical light emitting diode that is easy to arrange and shape the nanostructure To provide a method.

In order to achieve the above object, the present invention has at least one p-electrode in the p-type semiconductor layer formed on the substrate, at least one n-electrode in the n-type semiconductor layer, p-type semiconductor layer and n-type semiconductor 1. A method of manufacturing a vertical light emitting diode having an active layer between layers, the method comprising: 1) applying an upper portion of a vertical light emitting diode as a photosensitive agent and introducing a photolithography process to expose only the n-type semiconductor layer; 2) immersing the vertical light emitting diode exposed to the n-type semiconductor layer of step 1) in a zinc precursor solution, taking out the immersed vertical light emitting diode and applying heat to form a zinc oxide seed on the vertical light emitting diode; And 3) immersing the vertical light emitting diode in which the zinc oxide seed is formed on the n-type semiconductor layer of step 2) in a mixture of the zinc precursor and the surfactant, and applying heat to form the zinc oxide nanostructure on the vertical light emitting diode. It provides a method of manufacturing a vertical light emitting diode comprising a.

In addition, step 3) requires an additional step for removing the photoresist, ungrown zinc oxide crystals used in step 1) from the vertical light emitting diode. Preferably, the vertical light emitting diode on which the zinc oxide nanostructure is formed may be immersed in an organic solvent, subjected to ultrasonic treatment, and then dried. At this time, the organic solvent may be used acetone, C ₁ ~ C ₃ alcohol or a mixture thereof.

The n-type semiconductor layer is a portion located above the vertical light emitting diode, and the light emitted from the vertical light emitting diode is emitted, the n-type semiconductor layer may be transparent. Preferred n-type semiconductor layers are gallium nitride (GaN), aluminum gallium nitride (AlGaN), indium aluminum gallium nitride (InAlGaN), and the like.

In addition, the zinc precursor of steps 2) and 3) may be used zinc acetate, zinc nitrate, zinc sulfate, zinc chloride and the like. The zinc precursor is added to distilled water, C ₁ ~ C ₃ alcohol, ammonia or a mixture thereof to prepare a 0.0001 ~ 10 molar concentration, it can be heated to 25 ~ 200 ℃ to prepare a zinc precursor solution. The vertical light emitting diode immersed in the zinc precursor solution of step 2) may be heated at 25 ° C. to 200 ° C. for 10 to 600 minutes, and a method of applying heat may be performed by a conventional method in the art. Preferably, the vertical light emitting diode immersed in the zinc precursor solution may be put in a dryer, and heat may be applied by selecting the appropriate temperature and time.

In addition, the surfactant of step 3) may be used hexamethylenetetramine, urea, ammonia, etc., and the zinc precursor and the surfactant is added to distilled water, C ₁ ~ C ₃ alcohol, ammonia or a mixture thereof, respectively, 0.0001 The zinc precursor and the surfactant mixture may be prepared at a concentration of ˜10 moles. Heat may be applied to the vertical light emitting diode immersed in the mixed solution of step 3) at 25 to 200 ° C. for 10 to 600 minutes, and the heating may be performed by a conventional method in the art. Preferably, the vertical light emitting diode immersed in the mixed solution may be put in a dryer, and heat may be applied by selecting the appropriate temperature and time.

The zinc oxide nanostructures formed on the n-type semiconductor layer according to the present invention may be prepared nanowires, nanorods, nanowalls, nanoballs, nanotubes, etc., preferably nanowires, nanorods, etc. have. In this case, growth of the zinc oxide nanostructures may be controlled to have a vertical, oriented or random texturing structure, and the zinc oxide nanostructures may have a diameter and a length of 5 nm to 50 μm.

In addition, the present invention provides a vertical light emitting diode manufactured according to the manufacturing method of the present invention. The vertical light emitting diode of the present invention may have a light emission wavelength in the range of 200 to 1000 nm.

The light emitting diode is used as a light source for high efficiency lighting, and the light emitting diode has a multilayer structure. The semiconductor material for manufacturing the light emitting diode may be manufactured using an organic semiconductor material in addition to inorganic semiconductor materials such as gallium nitride, silicon, and other compound semiconductors of arsenic gallium.

In general, although the growth on the light emitting diode sapphire substrate, such a sapphire substrate is a hard, electrically non-conductor and poor thermal conductivity properties, there is a limit in reducing the size of the light emitting diode to reduce the manufacturing cost or improve the characteristics of the light output and the chip. In particular, it is important to solve the heat dissipation problem of the light emitting diode because a large current is required for the high output of the light emitting diode. As a means to solve this problem, a vertical light emitting diode having a sapphire substrate removed using a laser lift-off technique has been proposed.

Various methods have been applied to improve light extraction efficiency in such vertical light emitting diodes. Although an etching method has been introduced to make the n-type semiconductor layer located on the top of the vertical light emitting diode bumpy, there is a disadvantage in that the work is cumbersome. In addition, such an etching method forms a very unstable surface state of nitrogen polarity, which may adversely affect device stability.

In addition, a method of generating zinc oxide structures on top of the vertical light emitting diode by using chemical vapor deposition has been studied, but since the chemical vapor deposition is performed at a high temperature of at least 300 ° C., the n-electrode portion of the vertical light emitting diode has no thermal damage. There is a disadvantage that the driving voltage is increased. While overcoming the above disadvantages, the method of stacking the oxide nanostructure on the n-type semiconductor layer in order to increase the light extraction efficiency of the vertical light emitting diode is most preferred. The n-type semiconductor layer may be any material used in the art without limitation, and the n-type semiconductor layer may be transparent. As a material that may be used as the n-type semiconductor layer, GaN, AlGaN, InAlGaN, or the like may be used.

The present invention is to laminate a zinc oxide nanostructure on the vertical light emitting diode at a low temperature, it can be carried out using a wet method. Preferred wet methods include the sol-gel method and the micro bubble method. The sol-gel method and the micro bubble method can be introduced and used without limitation as long as it can be used in the art.

First, step 1) is a step of introducing a photolithography process to expose only the n-type semiconductor layer on the vertical light emitting diode.

In the wet method, an n-type semiconductor layer and an n-electrode may be exposed on the top surface of the vertical light emitting diode. The present invention requires exposing only the n-type semiconductor layer to form a zinc oxide nanostructure on the n-type semiconductor layer of the vertical light emitting diode. The method of exposing only the n-type semiconductor layer can be easily exposed through a photolithography process, which is a conventional method in the art. Preferably, the upper part of the vertical light emitting diode is coated with a photosensitive agent reacting to a light source, Based on the light source, only the n-type semiconductor layer may be exposed through a positive lithography or a negative lithography process.

The photosensitizer generally refers to an organic or inorganic composition in which physical and chemical changes occur under the action of light and radiation energy, or a composition system in which an image is formed by light irradiation. The photosensitizer may be used a conventional material used in the semiconductor industry, or can be purchased and used. In particular, the photosensitizer is most preferably used to react with ultraviolet light.

Next, step 2) is a step of forming a zinc oxide seed on the n-type semiconductor layer of the vertical light emitting diode of step 1).

In order to form a zinc oxide seed on the n-type semiconductor layer, the zinc oxide seed may be formed through an immersion process or a spin coating method which is conventional in the art. Preferably, the zinc precursor is dissolved in a solution, and the vertical light emitting diode may be immersed therein for a predetermined time to form a zinc oxide seed. As a preferable zinc precursor, zinc acetate, zinc nitrate, zinc sulfate, zinc chloride, etc. can be used individually or in mixture of 2 or more types.

In the present invention, the zinc oxide seedranch zinc precursor is formed having a crystal structure on the n-type semiconductor layer and refers to a zinc oxide crystal bonded to the n-type semiconductor layer. In this case, the method of forming the zinc oxide seed using the zinc precursor may be performed by evaporating the zinc oxide powder to deposit it on the n-type semiconductor layer, or by applying zinc oxide powder directly to the n-type semiconductor layer. Preferably, the zinc precursor may be dissolved in distilled water, C ₁ -C ₃ alcohol, ammonia or a mixture thereof, and the zinc oxide seed may be formed by immersing the vertical light emitting diode for a predetermined time. In this case, the zinc precursor is prepared by adding 0.0001-10 mol to distilled water, C ₁ -C ₃ alcohol, ammonia or 1 L of these mixtures, and heating the zinc precursor solution to 25-200 ° C. to ionize the zinc precursor solution. And can be activated. The method of applying heat to the zinc precursor solution is possible in a conventional manner, it can be applied under a constant pressure depending on the temperature conditions.

When the zinc precursor solution is prepared, when the heating temperature is less than 25 ° C., the zinc precursor is not sufficiently dissolved and the zinc precursor has a low ionization rate, which makes it difficult to form zinc oxide seeds. When the temperature is above 200 ° C., the vertical light emitting diode is immersed. In order to reduce the temperature of the solution, it is not efficient. Furthermore, when the vertical light emitting diode having the photosensitive agent remaining in the solution is immersed in a solution exceeding 200 ° C., the photosensitive agent is denatured on the vertical light emitting diode, so that it is difficult to remove thereafter.

Subsequently, the time for immersing the vertical light emitting diode in the zinc precursor solution may be selected in consideration of the concentration and temperature of the zinc precursor solution, and the time for immersing the vertical light emitting diode in the zinc precursor solution. Soak for ~ 60 minutes.

Next, after the zinc oxide seed is formed on the n-type semiconductor layer through the above step, it is possible to induce the growth of the nanostructure through the formed zinc oxide seed. Therefore, it is necessary to apply heat to the vertical light emitting diode so that the zinc oxide seed can be fixed to the vertical light emitting diode. The method of applying heat of the immersed vertical light emitting diode is not particularly limited, and heat is preferably applied using a dryer. At this time, it is preferable to make heat into 25-200 degreeC, and to apply heat. When the temperature to apply the heat is less than 25 ℃, it is not easy to fix the zinc oxide crystals to the vertical light emitting diode, and when the heating temperature exceeds 200 ℃, it is easy to fix the zinc oxide crystals, but vertical light emission There is a disadvantage that can cause damage to the diode n-electrode. In addition, due to the denaturation of the photoresist remaining in the vertical light emitting diode, there is a disadvantage that it is difficult to remove later.

Finally, step 3) is a step of forming a zinc oxide nanostructure using a vertical light emitting diode formed with zinc oxide seed.

The surfactant used in the step 3) is to serve as a catalyst for the rapid formation of the zinc oxide nanostructure, to continuously supply OH ^- ions and the like. Preferably, hexamethylenetetramine, urea, ammonia, or the like may be used.

In order to grow a zinc oxide seed formed on the vertical light emitting diode n-type semiconductor layer into a zinc oxide nanostructure, a zinc precursor and a surfactant mixture may be prepared and used. The zinc precursor and the surfactant mixture may be prepared by dissolving in distilled water, C ₁ ~ C ₃ alcohol, ammonia or a mixture thereof. At this time, the addition amount of the zinc precursor and the surfactant is not limited as long as it is a preferable ratio capable of forming the zinc oxide nanostructure in the zinc oxide seed, more preferably the zinc precursor and the surfactant is the distilled water, C ₁ ~ C ₃ alcohol, It can be prepared by adding 0.0001 to 10 mol of ammonia or 1 L of these mixtures, respectively.

Heat may be added to ionize and activate the zinc precursor and surfactant mixture, and preferably heated to 25 to 200 ° C. to ionize and activate the zinc precursor and surfactant mixture. The method of applying heat to the mixture of zinc precursor and surfactant may be applied under a constant pressure, if possible, according to a conventional method.

When the heating temperature of the mixed solution is less than 25 ℃, not only the zinc precursor and the surfactant is not sufficiently dissolved, but also not ionized and activated, it is difficult to induce zinc oxide nanostructure formation smoothly. When the temperature of the mixed liquid exceeds 200 ° C., the mixed liquid is ionized and activated. However, in order to immerse the vertical light emitting diode in which the zinc oxide seeds are formed, it is troublesome to lower the temperature of the mixed liquid. Furthermore, if the vertical light emitting diode having the photoresist remaining is immersed in the mixed solution exceeding 200 ° C., the photosensitive agent is deformed on the vertical light emitting diode, so that it is difficult to remove thereafter.

In order to immerse the vertical light emitting diode in the mixed solution prepared in step 3) and to ensure that the zinc oxide seed formed on the vertical light emitting diode is formed of zinc oxide nanostructures, while maintaining the temperature of the mixed solution at 25 ~ 200 ℃ To perform. The temperature range is the most preferred temperature range for the zinc oxide seed to be formed into a zinc oxide nanostructure. The time for forming the zinc oxide nanostructures in the vertical light emitting diode may be varied by the concentration and temperature of the mixed solution. Preferably it may be performed for 10 to 600 minutes.

Zinc oxide nanostructures refer to nanomaterials of all shapes having diameters and lengths of 5 nm to 50 μm. Preferably the nanostructures are nanowires, nanorods, nanowalls, nanoballs, nanotubes and the like, more preferably nanowires, nanorods and the like.

The nanowires refer to nanowire-shaped nanomaterials having a diameter and a length of 5 nm to 50 μm. In addition, the nanorods refer to a rod-shaped nanomaterial having an inside filling having a diameter and a length of 5 nm to 50 μm.

The growth direction of the nanostructure on the vertical light emitting diode n-type semiconductor layer may be controlled in any direction, and may be preferably grown to have a vertical, orientation, random texturing structure, and the like.

The oriented structure refers to a form in which the nanostructures are grown in a predetermined direction, not vertical, and the random texturing structure refers to a form in which the growth direction is grown in a random direction, not in a constant direction.

The nanostructure manufactured by the manufacturing method is characterized in that it is formed only on the vertical light emitting diode n-type semiconductor layer, the nanostructure is a structure that can extract light emitted through the n-type semiconductor layer more effectively If it is not limited. In addition, the growth direction of the nanostructure is not limited to the growth direction as long as the light extraction efficiency is the best direction. The diameter and length of the grown nanostructures are not limited as long as they have the best light extraction efficiency.

The present invention may further include removing impurities other than the zinc oxide nanostructures formed on the vertical light emitting diodes.

In order to form a zinc oxide nanostructure on the n-type semiconductor layer of the vertical light emitting diode in the present invention, the vertical light emitting diode was applied as a photosensitive agent in step 1). The photosensitizer was used as a mask to selectively produce the zinc oxide nanostructures only in the vertical light emitting diode n-type semiconductor layer. Therefore, in this step, it is necessary to remove the photosensitizer and ungrown zinc oxide residue (hereinafter collectively referred to as impurities).

The method for removing impurities is not limited if the conventional methods in the art, preferably, the step 3) of zinc vertical light emitting diode of the organic solvent nanostructure is formed, for example acetone, C ₁ ~ C ₃ alcohol, oxidation, It can be removed by immersion in ammonia or a mixture thereof. In order to facilitate the removal of impurities present in the vertical light emitting diode, the vertical light emitting diode may be performed by applying ultrasonic waves while being immersed in an organic solvent.

In addition, the present invention provides a vertical light emitting diode manufactured according to the manufacturing method of the present invention. The vertical light emitting diode of the present invention forms a zinc oxide nanostructure on the light emitting diode n-type semiconductor layer to increase light extraction efficiency, and the vertical light emitting diode may have a light emission wavelength in a range of 200 to 1000 nm. The wavelength range is a wavelength range including all ultraviolet rays, infrared rays, visible light, and the like.

Examples of a method of manufacturing a vertical type light emitting diode having a photonic crystal structure according to the present invention can be variously applied, and hereinafter, preferred embodiments will be described with reference to the accompanying drawings.

1 is a schematic diagram showing the steps for forming a vertical light emitting diode zinc oxide seed by wet chemical synthesis. In detail, the vertical light emitting diode 3 from which the photosensitive agent has been removed is immersed in the zinc precursor solution 2 so that the vertical light emitting diode n-type semiconductor layer is exposed, and the reaction is performed in the heating apparatus 1 having a heat transfer plate. have. In this drawing, it can be seen that the zinc oxide seed 40 may be formed even on a simple process on the n-type semiconductor layer.

In addition, Figure 2 is a schematic diagram showing the step of forming a zinc oxide nanostructure from the zinc oxide seed formed on the vertical light emitting diode n-type semiconductor layer by a wet chemical synthesis method. In detail, the vertical light emitting diode 3 in which the zinc oxide seed was formed was fixed to the fixing device 32, and immersed in the zinc precursor and the surfactant mixture liquid 31. It can be seen that a vertical light emitting diode in which a zinc oxide nanostructure 50 is formed by inducing a reaction in a heating device 1 having a heat transfer plate is manufactured.

3 is a view illustrating a process of manufacturing a zinc oxide nanostructure on the n-type semiconductor layer 24 of the vertical light emitting diode 3. In detail, (a) is a view showing a general vertical light emitting diode, and in order to form a zinc oxide nanostructure only on the light emitting diode (3) n-type semiconductor layer 24, the photoresist of the vertical light emitting diode (3) is (30), a photolithography step is introduced to remove the photosensitive agent in the n-type semiconductor layer 24 (see (b)). The zinc oxide seed 40 is produced in the n-type semiconductor layer 24 using a zinc precursor in the vertical light emitting diode 3 (see (c)). Appropriate conditions are introduced into the vertical light emitting diode in which the zinc oxide seed is generated, thereby producing the zinc oxide nanostructure 50 (see (d)). Since the photoresist 30 remains in the vertical light emitting diode 3 in which the zinc oxide nanostructure 50 is formed, the photoresist 30 is removed under appropriate conditions, and the zinc oxide is deposited on the n-type semiconductor layer 24. The vertical light emitting diode 3 in which the nanostructure 50 was produced was manufactured (see (e)). The zinc oxide nanostructure 50 is a structure for more efficiently extracting light emitted from the vertical light emitting diode, and is not limited as long as the light extraction efficiency is good. Preferably, nanostructures such as nanowires and nanorods are preferred.

4 is an electron micrograph of observing that zinc oxide nanostructures formed on the vertical light emitting diode n-type semiconductor layer are formed. As can be seen in FIG. 4, it can be seen that the zinc oxide nanostructures are appropriately formed in the entire n-type semiconductor layer.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

However, the following examples are illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

<Example 1> Preparation of a transparent electrode ZnO nanostructures on top 1

Zinc acetate powder was diluted to 0.91 g in 1 L of distilled water, and heated to about 90 ° C. or higher for easy ionization and activation. A vertical light emitting diode was added to the acetic acid solution and maintained for 5 minutes to form zinc seeds, and heat treated at 90 ° C. in a drier.

Next, dilute zinc nitrate powder to 7.43 g in 1 L of distilled water, dilute hexamethylenetetramine powder as a surfactant to 3.50 g in a solution containing zinc nitrate, and then dissolve the zinc nitrate and hexamethylene tetra. The Min mixture was heated to about 90 ° C. or higher to facilitate ionization and activation. Vertical light emitting diodes formed with zinc oxide seeds were immersed in a mixed solution of zinc nitrate and hexamethylenetetramine. In order to form zinc oxide nanowires or nanorods, the vertical light emitting diodes were maintained in a 90 ° C. mixed solution for 5 minutes.

In order to remove photoresist and ungrown zinc oxide residue from the vertical light emitting diode, it was immersed in ethanol solution and sonicated. This was dried to prepare a vertical light emitting diode in which a zinc oxide nanostructure was formed.

1 is a schematic diagram showing the steps for forming a zinc oxide seed on a vertical light emitting diode by a wet chemical synthesis method.

FIG. 2 is a schematic diagram showing a step of forming a zinc oxide nanostructure from a zinc oxide seed formed on an n-type semiconductor layer by a wet chemical synthesis method.

3 is a view illustrating a process of manufacturing a zinc oxide nanostructure on the n-type semiconductor layer of a vertical light emitting diode.

4 is an electron micrograph of the zinc oxide nanostructures formed on the upper surface of the vertical light emitting diode.

Explanation of symbols on the main parts of the drawings

1. Heater 2. Zinc precursor solution

3. Vertical Light Emitting Diode 10. Substrate

11.Ti / Au layer 12.Si submount

13. Au / Sn layer 21.p-electrode

22. p-type semiconductor layer 23. Multi-quantum well layer

24. n-type semiconductor layer 25. n-electrode

30. Photosensitizer 31. Zinc precursor and surfactant mixture

32. Fixer 40. Zinc oxide seed

50. Zinc Oxide Nanostructures

Claims

A vertical light emitting diode having at least one p-electrode in the p-type semiconductor layer formed on the substrate, at least one n-electrode in the n-type semiconductor layer, and an active layer between the p-type semiconductor layer and the n-type semiconductor layer In the manufacturing method of

1) applying an upper portion of the vertical light emitting diode to the photosensitive agent, and introducing only a photolithography process to expose only the n-type semiconductor layer;

2) immersing the vertical light emitting diode exposed to the n-type semiconductor layer of step 1) in a zinc precursor solution, taking out the immersed vertical light emitting diode and applying heat to form a zinc oxide seed on the vertical light emitting diode; And

3) immersing a vertical light emitting diode having a zinc oxide seed formed on the n-type semiconductor layer of step 2) in a mixture of zinc precursor and surfactant, and applying heat to form a zinc oxide nanostructure on top of the vertical light emitting diode A manufacturing method of a vertical light emitting diode comprising a.

The method of claim 1, further comprising immersing the vertical light emitting diode of step 3) in an organic solvent, treating the ultrasonic wave, and drying the vertical light emitting diode.

The method of claim 1, wherein the zinc precursor of steps 2) and 3) is used to manufacture a vertical light emitting diode, characterized in that at least one selected from the group consisting of zinc acetate, zinc nitrate, zinc sulfate and zinc chloride. Way.

According to claim 1, wherein the zinc precursor solution of step 2) is prepared by adding the zinc precursor to distilled water, C ₁ ~ C ₃ alcohol ammonia or a mixture thereof at a 0.0001 ~ 10 molar concentration, it is heated to 25 ~ 200 ℃ Method for producing a vertical light emitting diode, characterized in that the manufacturing.

The method of claim 1, wherein the n-type semiconductor layer is one selected from the group consisting of GaN, AlGaN, and InAlGaN.

The method of claim 1, wherein heat is applied to the vertical light emitting diode immersed in step 2) at 25 to 200 ° C. for 10 to 600 minutes.

The method of claim 1, wherein the surfactant of step 3) is at least one member selected from the group consisting of hexamethylenetetramine, urea and ammonia.

The method according to claim 1, wherein the zinc precursor and the surfactant mixture of step 3) is prepared by adding the zinc precursor and the surfactant to distilled water, C ₁ ~ C ₃ alcohol, ammonia or a mixture thereof at a concentration of 0.0001 to 10 mol, respectively. Method of manufacturing a vertical light emitting diode, characterized in that.

The method of claim 1, wherein heat is applied to the vertical light emitting diode immersed in step 3) at 25 to 200 ° C. for 10 to 600 minutes.

The method of claim 2, wherein the organic solvent is acetone, C ₁ -C ₃ alcohol, ammonia, or a mixture thereof.

The method of claim 1, wherein the zinc oxide nanostructure is at least one selected from the group consisting of nanowires, nanorods, nanowalls, nanoballs, and nanotubes.

12. The method of claim 11, wherein the zinc oxide nanostructure is at least one member selected from the group consisting of nanowires and nanorods.

The method of claim 1, wherein the growth of the zinc oxide nanostructure on the n-type semiconductor layer is controlled to have a vertical, oriented, or random texturing structure.

The method of claim 1, wherein the zinc oxide nanostructure has a diameter and a length of about 5 nm to 50 μm.

A vertical light emitting diode manufactured by the method of any one of claims 1 to 14.

16. The vertical light emitting diode of claim 15, wherein the light emitting wavelength range of the light emitting diode is 200 to 1000 nm.