Single-chip multiband light-emitting diode

Abstract

According to an embodiment, there is provided a light emitting diode (LED) comprising: an n-type nitride semiconductor layer; a V-pit generation layer located on the n-type nitride semiconductor layer and having a V-pit; an active layer located on the V-pit generation layer; and a p-type nitride semiconductor layer located on the active layer, wherein the active layer includes a well layer having a first well layer portion formed along a flat surface of the V-pit generation layer and a second well layer portion formed in the V-pit of the V-pit generation layer, and the LED emits light of at least two peak wavelengths at a single chip level.

Description

[Technical Field]

[0001] This disclosure relates to light-emitting diodes, and more particularly to light-emitting diodes that emit multiband light at the single-chip level. [Background technology]

[0002] Nitride semiconductors are used as light sources in display devices, traffic lights, lighting, and optical communication devices, and are primarily used in light-emitting diodes (LEDs) and laser diodes that emit blue or green light. Nitride semiconductors can also be used in heterojunction bipolar transistors (HBTs) and high electron-mobility transistors (HEMTs).

[0003] Generally, light-emitting diodes (LEDs) using nitride semiconductors have a heterojunction structure with a quantum well structure between the N-contact layer and the P-contact layer. The LED emits light based on the composition of the well layers within the quantum well structure. To increase internal quantum efficiency and reduce losses due to light absorption, LEDs are designed to emit light with a single-peak spectrum, i.e., monochromatic light.

[0004] Mixed-color light emitted from lighting sources, such as white light, cannot be realized as monochromatic light with a single peak. Therefore, techniques are commonly used to realize white light by using multiple light-emitting diodes that emit different monochromatic light together, or by using phosphors that convert the wavelength of light emitted from light-emitting diodes.

[0005] The use of phosphors involves problems such as the cost of the phosphor itself and efficiency degradation known as Stokes shift. It also involves numerous process problems for coating the phosphor onto the light-emitting diode, as well as issues such as yellowing of the phosphor support.

[0006] Furthermore, using a mixture of multiple light-emitting diodes complicates the process, as each diode must be manufactured from different materials, creating a cumbersome process. [Overview of the project] [Problems that the invention aims to solve]

[0007] If light with a multiband spectrum can be realized using a single-chip light-emitting diode, there is no need to use multiple light-emitting diodes or phosphors, thus solving many existing problems.

[0008] Attempts have been made to realize multiband spectral light by diversifying the composition of each well layer within conventional quantum well structures, but satisfactory results have not been obtained. In particular, since electron-hole recombination mainly occurs in specific well layers, it is difficult to generate multiband light.

[0009] The problem that this disclosure aims to solve is to provide a light-emitting diode with a novel structure that can realize multiband spectral light at the single-chip level. [Means for solving the problem]

[0010] A light-emitting diode according to one or more embodiments of the present disclosure includes an n-type nitride semiconductor layer, a V-pit generating layer located above the n-type nitride semiconductor layer and having V-pits, an active layer located on the V-pit generating layer, and a p-type nitride semiconductor layer located on the active layer. The active layer includes a well layer, the well layer having a first well layer portion formed along a flat surface of the V-pit generating layer and a second well layer portion formed within the V-pits of the V-pit generating layer. The light-emitting diode emits light of at least two peak wavelengths at a single-chip level.

[0011] The light emitting diodes according to one or more embodiments of the present disclosure include an n-type nitride semiconductor layer, a V-pit generation layer located above the n-type nitride semiconductor layer and having V-pits, an active layer located on the V-pit generation layer, a p-type AlGaN layer located on the active layer, and a p-type nitride semiconductor layer located on the p-type AlGaN layer. The active layer includes a well layer, and the well layer has a first well layer portion formed along a flat surface of the V-pit generation layer and a second well layer portion formed within the V-pits of the V-pit generation layer. The first well layer portion and the second well layer portion emit light with different peak wavelengths.

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic cross-sectional view for explaining a light emitting diode according to one or more embodiments of the present disclosure.

[0013] [Figure 2A] It is a schematic partial cross-sectional view showing a part of FIG. 1 enlarged for explaining a light emitting diode according to an embodiment of the present disclosure.

[0014] [Figure 2B] It is a schematic partial cross-sectional view showing a part of FIG. 2 enlarged for explaining a light emitting diode according to an embodiment of the present disclosure.

[0015] [Figure 3] It is a schematic perspective view showing the V-pit generation layer enlarged for explaining a light emitting diode according to one or more embodiments of the present disclosure.

[0016] [Figure 4A] It is a graph showing the emission spectrum of a yellow light emitting diode according to a comparative example.

[0017] [Figure 4B] It is a graph showing the emission spectrum of a light emitting diode according to Example 1.

[0018] [Figure 5A] This is a photograph for explaining the light emitted from the yellow light-emitting diode according to the comparative example.

[0019] [Figure 5B] This is a photograph for explaining the light emitted from the light-emitting diode according to Example 1.

[0020] [Figure 6A] This is a TEM photograph for explaining the V-pit of the yellow light-emitting diode according to the comparative example.

[0021] [Figure 6B] This is a TEM photograph for explaining the V-pit of the light-emitting diode according to Example 1.

[0022] [Figure 6C] This is a TEM photograph obtained by magnifying the quantum well structure of Fig. 6B.

[0023] [Figure 7A] This is a graph showing the emission spectrum of the light-emitting diode according to Example 2.

[0024] [Figure 7B] This is a graph showing the emission spectrum of the light-emitting diode according to Example 3.

[0025] [Figure 8A] This is a photograph for explaining the light emitted from the light-emitting diode according to Example 2.

[0026] [Figure 8B] This is a photograph for explaining the light emitted from the light-emitting diode according to Example 3.

[0027] [Figure 9A] This is a TEM photograph for explaining the V-pit of the light-emitting diode according to Example 2.

[0028] [Figure 9B] This is a TEM image illustrating the V-pit of the light-emitting diode according to Example 3.

[0029] [Figure 10] This graph shows the emission spectrum of the light-emitting diode package according to Example 4.

[0030] [Figure 11] This is a TEM image illustrating the V-pit of the light-emitting diode according to Example 4. [Modes for carrying out the invention]

[0031] The embodiments of this disclosure will be described in detail below with reference to the attached drawings. The embodiments described below are provided as examples to fully convey the ideas of this disclosure to a person ordinary in the art to which this disclosure pertains. Therefore, this disclosure is not limited to the embodiments described below and may be embodied in other forms. In the drawings, the width, length, thickness, etc., of components may be exaggerated for convenience. Also, when one component is described as being "on top of" or "above" another component, this includes not only cases where one component is "directly above" or "directly above" another component, but also cases where another component is interposed between one component and another. Throughout the specification, the same reference numerals indicate the same component.

[0032] A light-emitting diode according to one or more embodiments of the present disclosure includes an n-type nitride semiconductor layer, a V-pit generating layer located above the n-type nitride semiconductor layer and having V-pits, an active layer located on the V-pit generating layer, and a p-type nitride semiconductor layer located on the active layer. The active layer includes a well layer, the well layer having a first well layer portion formed along a flat surface of the V-pit generating layer and a second well layer portion formed within the V-pits of the V-pit generating layer, and emitting light of at least two peak wavelengths at a single-chip level.

[0033] In at least one modified example, multiband spectral light can be emitted without the use of phosphors, thus solving many of the problems of the conventional technology that arise from the use of phosphors.

[0034] The first well layer portion can emit light of a first peak wavelength, and the second well layer portion can emit light of at least one second peak wavelength.

[0035] In other modified examples, the first well layer portion can emit light with peak wavelengths in the yellow series, and the second well layer portion can emit light with peak wavelengths in the blue series.

[0036] In further variations, the first well layer portion can emit light with peak wavelengths in the yellow series, and the second well layer portion can emit light with peak wavelengths in the blue series and light with peak wavelengths in the green series.

[0037] The first well layer portion may have an even higher indium (In) content than the second well layer portion. Furthermore, the first well layer portion may be even thicker than the second well layer portion.

[0038] The light-emitting diode has a p-type Al interposed between the active layer and the p-type nitride semiconductor layer. x Ga 1-x The p-type AlGaN layer may further contain an N layer, and the Al composition ratio x in the p-type AlGaN layer is greater than 0 and less than 0.3.

[0039] Furthermore, the aforementioned p-type Al x Ga 1-x The N layer can have a thickness of less than 100 nm.

[0040] On the other hand, the V-pit generation layer can have a thickness exceeding 450 nm. Furthermore, each V-pit formed in the V-pit generation layer may include V-pits with an entrance width exceeding 300 nm.

[0041] On the other hand, the active layer may have a multiple quantum well structure having a plurality of well layers and a plurality of barrier layers, and may further include a capping layer covering the well layers between the well layers and the barrier layers, and the capping layer may contain Al.

[0042] Furthermore, the capping layer may contain 10 atomic percent or more of Al relative to the overall composition within the capping layer.

[0043] The p-type nitride semiconductor layer may include recesses on the V-pits.

[0044] In other modifications, the active layer can be in contact with the V-pit generating layer. That is, the barrier layer of the active layer may be formed directly on the V-pit generating layer.

[0045] A light-emitting diode according to one or more embodiments of the present disclosure includes an n-type nitride semiconductor layer, a V-pit generating layer located above the n-type nitride semiconductor layer and having V-pits, an active layer located on the V-pit generating layer, a p-type AlGaN layer located on the active layer, and a p-type nitride semiconductor layer located on the p-type AlGaN layer. The active layer includes a well layer, the well layer having a first well layer portion formed along a flat surface of the V-pit generating layer and a second well layer portion formed within the V-pits of the V-pit generating layer. The first well layer portion and the second well layer portion can emit light with different peak wavelengths.

[0046] The second well layer portion can emit light with shorter wavelengths compared to the first well layer portion. In one embodiment, the second well layer portion can emit light with at least two peak wavelengths.

[0047] On the other hand, the p-type AlGaN layer is a general formula Al x Ga 1-x This can be expressed as N, where the composition ratio x of Al in the p-type AlGaN layer may be greater than 0 and less than 0.3.

[0048] The p-type AlGaN layer can have a thickness of less than 100 nm.

[0049] On the other hand, the V-pit generation layer can have a thickness exceeding 450 nm, and each V-pit formed in the V-pit generation layer may include V-pits with an entrance width exceeding 300 nm.

[0050] Figure 1 is a schematic cross-sectional view illustrating a light-emitting diode according to one embodiment of the present disclosure. Figure 2A is a schematic partial cross-sectional view showing an enlarged portion of Figure 1 to illustrate a light-emitting diode according to one embodiment of the present disclosure. Figure 2B is a schematic partial cross-sectional view showing an enlarged portion of Figure 2A to illustrate a light-emitting diode according to one embodiment of the present disclosure. Figure 3 is a schematic perspective view showing an enlarged V-pit generation layer to illustrate a light-emitting diode according to one embodiment of the present disclosure.

[0051] First, referring to Figure 1, the light-emitting diode may include a substrate 21, a nucleus layer 23, a high-temperature buffer layer 25, an n-type nitride semiconductor layer 27, a V-pit generation layer 29, an active layer 30, a p-type AlGaN layer 31, and a p-type nitride semiconductor layer 33.

[0052] The substrate 21 is for growing a gallium nitride-based semiconductor layer and may be a sapphire substrate, a SiC substrate, a Si substrate, a spinel substrate, or the like. The substrate 21 may have protrusions as shown in Figure 1, and may be, for example, a patterned sapphire substrate. However, the disclosure is not limited thereto, and may also be a substrate having a flat top surface, such as a sapphire substrate.

[0053] The core layer 23 may be formed on the substrate 21 at a low temperature of 400°C to 600°C using (Al,Ga)N, and may, for example, be formed using AlGaN or GaN. The composition of the core layer 23 can be changed depending on the substrate 21. For example, if the substrate 21 is a patterned sapphire substrate, the core layer 23 may be formed using AlGaN, and if the substrate 21 is a sapphire substrate with a flat top surface, the core layer 23 may be formed using GaN. The core layer 23 may be formed to a thickness of, for example, about 25 nm.

[0054] The high-temperature buffer layer 25 may be grown at a relatively high temperature to mitigate the occurrence of defects such as dislocations between the substrate 21 and the n-type nitride semiconductor layer 27. The high-temperature buffer layer 25 may be formed of undoped GaN or GaN doped with n-type impurities. During the formation of the high-temperature buffer layer 25, a through-potential is generated due to lattice mismatch between the substrate 21 and the high-temperature buffer layer 25. The high-temperature buffer layer 25 may be formed to a thickness of, for example, about 4.2 μm.

[0055] The n-type nitride semiconductor layer 27 is a nitride-based semiconductor layer doped with n-type impurities, and may be formed, for example, from a Si-doped GaN layer. The Si doping concentration for the n-type nitride semiconductor layer 27 is 5E17 / cm³. 2 ~5E19 / cm 2 The n-type nitride semiconductor layer 27 may be grown using MOCVD technology by supplying a metal source gas into a chamber and growing it at 1000°C to 1200°C (e.g., 1050°C to 1100°C) under a growth pressure of 150 Torr to 200 Torr. In this case, the n-type nitride semiconductor layer 27 may be formed continuously on the high-temperature buffer layer 25, and the through-potential formed in the high-temperature buffer layer 25 may be transferred to the n-type nitride semiconductor layer 27. The n-type nitride semiconductor layer 27 may be formed relatively thinner than the high-temperature buffer layer 25, for example, with a thickness of about 2.5 μm.

[0056] The V-pit generation layer 29 is located above the n-type nitride semiconductor layer 27. In one embodiment of the present disclosure, the V-pit generation layer 29 may be formed of, for example, a GaN layer. The V-pit generation layer 29 may be grown at a relatively lower temperature than the n-type nitride semiconductor layer 27, for example, about 900°C, thereby forming each V-pit in the V-pit generation layer 29.

[0057] By growing the V-pit generation layer 29 at a relatively lower temperature than the n-type nitride semiconductor layer 27, the crystal quality is artificially reduced, and three-dimensional growth is promoted, thereby generating V-pits 29v.

[0058] As shown in Figure 3, each V-pit 29v can have a hexagonal pyramidal shape when the growth surface of the nitride semiconductor layer is the C-plane. Each V-pit 29v may be formed at the upper end of the through-potential.

[0059] The V-pit formation layer 29 may be formed with a thickness thinner than the n-type nitride semiconductor layer 27, for example, with a thickness of about 450 nm to 600 nm. The size of each V-pit 29v formed within the V-pit formation layer 29 can be adjusted through the growth conditions and growth time of the V-pit formation layer 29. In one embodiment, the maximum width of the entrance to the V-pit 29v formed in the V-pit formation layer 29 may generally exceed about 230 nm.

[0060] The thickness of the V-pit generation layer 29 particularly affects the size of the V-pit 29v. Furthermore, the size of the V-pit 29v is considered to affect the generation of multiband spectral light.

[0061] In this embodiment, the V-pit generation layer 29 is described as a single layer, but it is not limited to this, and the V-pit generation layer 29 may be a multilayer. For example, the V-pit generation layer 29 may include at least two layers from among GaN, AlGaN, InGaN, and AlGaInN layers.

[0062] The active layer 30 is located on the V-pit formation layer 29. The active layer 30 emits light by recombination of electrons and holes. And, as shown in FIGS. 2A and 2B, the active layer 30 can have a single quantum well structure or a multiple quantum well (MQW) structure in which barrier layers 30b and well layers 30w are alternately stacked.

[0063] The active layer 30 can be in contact with the V-pit formation layer 29, but the present disclosure is not limited thereto, and the active layer 30 may be formed along the V-pit 29v. The thickness of the active layer 30 formed in the V-pit 29v is smaller than the thickness of the active layer 30 formed on the flat surface of the V-pit formation layer 29. The thickness of the active layer 30 in the V-pit 29v can vary depending on the depth of the V-pit 29v. The thickness of the active layer 30 at an intermediate depth of the V-pit 29v may be about 1 / 3 or less of the thickness of the active layer 30 formed on the flat surface of the V-pit formation layer 29. In particular, the thickness of the well layer 30w at an intermediate depth of the V-pit 29v may be about 1 / 3 or less of the thickness of the well layer 30w formed on the flat surface of the V-pit formation layer 29.

[0064] On the other hand, the well layer 30w may be formed of In x Al y Ga 1-x-y N (0 < x < 1, 0 ≦ y < 1). The composition ratios of In, Al, and Ga can be selected according to the required light. In particular, the well layer 30w (hereinafter, the first well layer portion) formed on the flat surface of the V-pit formation layer 29 has a composition that emits light in the long wavelength side spectrum of the multi-band. On the other hand, the well layer 30w (hereinafter, the second well layer portion) formed in the V-pit 29v has a composition that emits light in the short wavelength side spectrum of the multi-band. For example, the indium (In) composition ratio in the first well layer portion is higher than the indium (In) composition ratio in the second well layer portion, the first well layer portion may be formed of InGaN so as to emit yellow series light, and the second well layer portion may be formed of InGaN so as to emit green and / or blue series light.

[0065] The second well layer portion may be formed with the same composition on each surface within the V-pit 29v, but is not limited to this, and may be formed with different compositions on each surface. This allows the light-emitting diode of the present disclosure to embody light having at least two bands at a single-chip level using the first well layer portion and the second well layer portion. In other words, a single chip comprising the first well layer portion and the second well layer portion enables the emission of light having at least two bands without the use of phosphors.

[0066] The barrier layer 30b may be formed of a nitride semiconductor layer such as GaN, InGaN, AlGaN, or AlInGaN, which has a wider band gap than the well layer 30w. For example, if the first well layer is formed of InGaN so as to emit yellow light, the barrier layer 30b may be formed of InGaN with a lower indium (In) content than the well layer 30w.

[0067] On the other hand, as shown in Figure 2B, a capping layer 30c may be interposed between the well layer 30w and the barrier layer 30b. The capping layer 30c may be formed before the deposition of the barrier layer 30b to prevent the In in the well layer 30w from dissociating during the deposition of the barrier layer 30b. The capping layer 30c may contain Al and may be formed of, for example, AlGaN or AlInGaN. The Al composition contained in the capping layer 30c may differ between the first capping layer portion, i.e., the capping layer portion located on the upper part of the flat surface of the V-pit generating layer 29, and the second capping layer portion, i.e., the capping layer portion formed within the V-pit 29v. The Al content in the first capping layer portion is greater than the Al content in the second capping layer portion. For example, the Al composition in the first capping layer portion may be 10 atomic percent or more, and even 12 atomic percent or more, relative to the total composition of the capping layer, and the Al composition in the second capping layer portion may be approximately 5 atomic percent or more relative to the total composition of the capping layer.

[0068] Each capping layer 30c may be formed with a thickness generally similar to or smaller than that of the adjacent well layer 30w.

[0069] The p-type AlGaN layer 31 is located on the active layer 30. The p-type AlGaN layer 31 can also be formed within the V-pit 29v. The Al composition ratio in the p-type AlGaN layer 31 is relatively low compared to the Al composition ratio used in the electron blocking layer. Furthermore, the Al composition ratio in the p-type AlGaN layer 31 may be smaller than the Al composition ratio in the capping layer 30c. For example, the p-type AlGaN layer 31 may be formed using the general formula Al x Ga 1-x It can be expressed as N, where x may be greater than 0 and less than 0.3. On the other hand, in one embodiment, the thickness of the p-type AlGaN layer 31 may be less than about 100 nm, and in a particular embodiment, it may be about 70 nm.

[0070] The p-type nitride semiconductor layer 33 may be formed from a semiconductor layer doped with p-type impurities such as Mg, for example, GaN. The p-type nitride semiconductor layer 33 may be a single layer or multiple layers and may include a p-type contact layer. As shown in Figure 1, the p-type nitride semiconductor layer 33 may have concave grooves in the V-pit 29v. Since the p-type nitride semiconductor layer 33 does not completely fill the V-pit 29v, it is possible to prevent the loss of light generated in the well layer 30w within the V-pit 29v.

[0071] Figure 4A is a graph showing the emission spectrum of the yellow light-emitting diode according to Comparative Example 1, and Figure 4B is a graph showing the emission spectrum of the light-emitting diode according to Example 1. On the other hand, Figure 5A is a photograph illustrating the light emitted from the yellow light-emitting diode according to Comparative Example 1, and Figure 5B is a photograph illustrating the light emitted from the light-emitting diode according to Example 1.

[0072] Comparative Example 1 and Example 1 used a sapphire substrate with a flat top surface as the growth substrate and grew each semiconductor layer under similar process conditions, differing only in the deposition time of the V-pit formation layer 29. Specifically, in Example 1, the deposition time of the V-pit formation layer 29 was even longer than in Comparative Example 1. Meanwhile, in Comparative Example 1 and Example 1, three well layers were formed in each.

[0073] Referring to Figures 4A and 5A, under a current strength of 50 mA, Comparative Example 1 exhibited a single-band spectrum with a single peak in the yellow wavelength band. The light emitted from the light-emitting diode of Comparative Example 1 was clearly yellow, as shown in Figure 5A.

[0074] Referring to Figures 4B and 5B, under a current strength of 50 mA, Example 1 exhibited a multiband spectrum with peaks in the yellow, green, and blue wavelength bands, respectively. The light emitted from the light-emitting diode of Example 1 was a cool white color, as shown in Figure 5B.

[0075] On the other hand, Figure 6A is a TEM image illustrating the V-pit of the yellow light-emitting diode according to Comparative Example 1, and Figure 6B is a TEM image illustrating the V-pit of the light-emitting diode according to Example 1.

[0076] Referring to Figures 6A and 6B, the sizes of the V-pits after the active layer is formed are approximately 309 nm and 362 nm, respectively. Thus, it can be confirmed that the V-pits in Example 1 are even larger than those in Comparative Example 1. In other words, the size of the V-pits can be adjusted by adjusting the deposition time of the V-pit formation layer.

[0077] As shown in Figures 6A and 6B, Comparative Example 1 and Example 1 differed in the thickness of the V-pit formation layer 29, and it can be concluded that the size of the V-pit affected the spectral band. In particular, Example 1 showed clear peaks not only in the green series but also in the blue series wavelength band. This is judged to be due to the fact that the second well layer portions formed within the V-pit 29v were formed with different compositions and / or different thicknesses.

[0078] Figure 6C is a magnified TEM image of the quantum well structure shown in Figure 6B.

[0079] Referring to Figure 6C, it can be confirmed that an Al-containing capping layer 30c is formed on the well layer 30w, and a barrier layer 30b is formed on top of that. Here, it can be confirmed that the thickness of the well layer 30w is approximately 3.3 nm to 3.4 nm, and each capping layer 30c is approximately 2.8 nm to 3.0 nm thick.

[0080] On the other hand, component analysis of the first and second well layers via APT (atom probe tomography) confirmed that the first well layer had a relatively higher indium (In) content compared to the second well layer. On the APT graph, the indium (In) content of the first and second well layers was approximately 25% and 10.6%, respectively, for Comparative Example 1, and approximately 25.4% and 12.6%, respectively, for Example 1.

[0081] Figure 7A is a graph showing the emission spectrum of the light-emitting diode according to Example 2, and Figure 7B is a graph showing the emission spectrum of the light-emitting diode according to Example 3. On the other hand, Figure 8A is a photograph illustrating the light emitted from the light-emitting diode according to Example 2, and Figure 8B is a photograph illustrating the light emitted from the light-emitting diode according to Example 3. Furthermore, Figure 9A is a TEM image illustrating the V-pit of the light-emitting diode according to Example 2, and Figure 9B is a TEM image illustrating the V-pit of the light-emitting diode according to Example 3.

[0082] In both Examples 2 and 3, a patterned sapphire substrate was used as the growth substrate, and the growth conditions for the V-pit formation layer 29 were the same as in Example 1, forming five well layers within the quantum well structure. However, in Example 3, the indium (In) content in the well layers was reduced compared to Example 2.

[0083] Referring to Figures 7A and 7B, both Examples 2 and 3 showed spectra with peak wavelengths in the blue series as well as the yellow series. Furthermore, increasing the current strength resulted in a greater increase in the intensity of the long-wavelength peaks than in the short-wavelength peaks. In addition, the intensity of the short-wavelength peaks was highest at a current strength of 500 mA, and the value at 700 mA was even lower than the value at 300 mA.

[0084] Referring to Figures 8A and 8B, under the same current intensity of 300mA, Example 2 showed a pink color, while Example 3 showed a white light.

[0085] Referring to Figures 9A and 9B, the sizes of the V-pits after the active layer was formed were approximately 364 nm and 359 nm, respectively, which were similar to the V-pit sizes in Example 1. In other words, it was determined that the size of the V-pits is not significantly affected by the type of sapphire substrate, such as a flat sapphire substrate or a patterned sapphire substrate.

[0086] On the other hand, on the APT graph, the indium (In) content of the first well layer and the second well layer was approximately 26.6% and 11.6% in Example 2, and approximately 27% and 10% in Example 3.

[0087] Example 1 uses a sapphire substrate with a flat surface, while Examples 2 and 3 use a patterned sapphire substrate as the growth substrate. It can be seen that the spectral bands of light emitted from the light-emitting diode differ depending on the type of growth substrate.

[0088] Figure 10 is a graph showing the emission spectrum of the light-emitting diode package according to Example 4, and Figure 11 is a TEM photograph illustrating the V-pit of the light-emitting diode according to Example 4.

[0089] The light-emitting diode of Example 4 was formed under the same conditions as in Example 2, except that the deposition time of the V-pit formation layer was reduced. On the other hand, the light-emitting diode of Example 4 was 480 × 920 μm 2 The chip was fabricated as an area-based chip, sealed with transparent molding, and then the electroluminescent (EL) intensity was measured at different wavelengths, yielding the results shown in Figure 10.

[0090] Referring to Figure 10, the light-emitting diode of Example 4 clearly showed peaks in the blue region and the yellow region under current strengths of 50 mA or more, and the intensity at the peak wavelength increased as the current strength increased.

[0091] Referring to Figure 11, the size of the V-pit entrance was approximately 230 nm. When using a patterned sapphire substrate as the growth substrate, it is possible to provide light-emitting diodes with two distinct peak wavelengths even with a relatively smaller V-pit size compared to when using a flat sapphire substrate. On the other hand, when using a flat sapphire substrate, it is necessary to increase the indium (In) composition ratio of the well layer compared to when using a patterned sapphire substrate in order to provide light-emitting diodes with two or more peak wavelengths with a V-pit size of around 230 nm.

[0092] The light-emitting diodes described above can be manufactured as various chips and used in a variety of applications. For example, the light-emitting diodes may be manufactured as vertical, horizontal, or flip-chip type light-emitting diode chips. Furthermore, the light-emitting diodes may be manufactured as standard-sized light-emitting diode chips, or as micro-LEDs or mini-LEDs. The light-emitting diodes may be used not only as illumination sources, but also as backlight sources or display sources.

[0093] As explained above, the specific details of this disclosure have been provided by embodiments with reference to the attached drawings. However, since the above explanation merely provides examples of the disclosure, it should not be understood that this disclosure is limited only to those embodiments. The scope of rights of this disclosure should be understood in terms of the claims and equivalent concepts described later. [Explanation of Symbols]

[0094] 21 circuit boards 23 Nuclear layer 25 High-temperature buffer layer 27 n-type nitride semiconductor layer 29 V-pit generation layer 29V V-Pit 30 Active layer 30b Barrier layer 30c capping layer 30W well layer 31 p-type AlGaN layer 33 p-type nitride semiconductor layer

Claims

1. n-type nitride semiconductor layer and; A V-pit generating layer located above the n-type nitride semiconductor layer and having V-pits; The active layer located on the V-pit generation layer; The active layer comprises a p-type nitride semiconductor layer located above the active layer; The activated layer includes a well layer, the well layer having a first well layer portion formed along the flat surface of the V-pit generating layer and a second well layer portion formed within the V-pits of the V-pit generating layer, Without using phosphors, it emits light with at least two peak wavelengths at the single-chip level. Of the two peak wavelengths, one peak wavelength that is longer than the other peak wavelength has a lower peak intensity than the other peak wavelength. A light-emitting diode in which the intensity of the valley located between the two peak wavelengths is lower than half the peak intensity of one of the two peak wavelengths.

2. The light-emitting diode according to claim 1, wherein the first well layer portion emits light of a first peak wavelength, and the second well layer portion emits light of at least one second peak wavelength.

3. The first well layer emits light with peak wavelengths in the yellow series, The light-emitting diode according to claim 2, wherein the second well layer portion emits light with a peak wavelength in the blue series.

4. The first well layer emits light with peak wavelengths in the yellow series, The light-emitting diode according to claim 2, wherein the second well layer portion emits light with peak wavelengths in the blue series and light with peak wavelengths in the green series.

5. The light-emitting diode according to claim 1, wherein the first well layer portion has an even higher indium (In) content than the second well layer portion.

6. The light-emitting diode according to claim 5, wherein the first well layer portion is even thicker than the second well layer portion.

7. p-type Al interposed between the active layer and the p-type nitride semiconductor layer ｘ Ga １－ｘ It further contains an N layer, The p-type Al ｘ Ga １－ｘ The light-emitting diode according to claim 1, wherein the composition ratio x of Al in the N layer is greater than 0 and less than 0.

3.

8. The p-type Al ｘ Ga １－ｘ The light-emitting diode according to claim 7, wherein the N layer has a thickness of less than 100 nm.

9. The light-emitting diode according to claim 1, wherein the V-pit generation layer has a thickness of more than 450 nm.

10. The light-emitting diode according to claim 9, wherein the V-pits formed in the V-pit generation layer include V-pits with an entrance width exceeding 230 nm.

11. The active layer has a multi-quantum well structure having multiple well layers and multiple barrier layers. The system further includes a capping layer interposed between the well layer and the barrier layer, and covering the well layer. The light-emitting diode according to claim 1, wherein the capping layer contains Al.

12. The light-emitting diode according to claim 11, wherein the capping layer contains 10 atomic percent or more of Al relative to the overall composition within the capping layer.

13. The light-emitting diode according to claim 1, wherein the p-type nitride semiconductor layer includes a recess on the V-pit.

14. The light-emitting diode according to claim 1, wherein the active layer is in contact with the V-pit generating layer.

15. n-type nitride semiconductor layer and; A V-pit generating layer located above the n-type nitride semiconductor layer and having V-pits; The active layer located on the V-pit generation layer; A p-type AlGaN layer located on the aforementioned active layer; The p-type AlGaN layer comprises; The activated layer includes a well layer, the well layer having a first well layer portion formed along the flat surface of the V-pit generating layer and a second well layer portion formed within the V-pits of the V-pit generating layer, The first well layer portion emits light with a first peak wavelength, and the second well layer portion emits light with a second peak wavelength different from the first peak wavelength. Of the first and second peak wavelengths, the peak wavelength that is longer than the other peak wavelength has a lower peak intensity than the peak intensity of the other peak wavelength. The intensity of the trough located between the first and second peak wavelengths is lower than half the peak intensity of one of the first and second peak wavelengths. Light-emitting diodes that do not contain phosphors.

16. The light-emitting diode according to claim 15, wherein the second well layer portion emits light with a shorter wavelength than the first well layer portion.

17. The light-emitting diode according to claim 16, wherein the second well layer portion emits light of at least two peak wavelengths, and the two peak wavelengths are different from the first peak wavelength.

18. The aforementioned p-type AlGaN layer is formed by the general formula Al ｘ Ga １－ｘ The light-emitting diode according to claim 15, wherein the composition ratio x of Al in the p-type AlGaN layer is expressed as N, and is greater than 0 and less than 0.

3.

19. The light-emitting diode according to claim 18, wherein the p-type AlGaN layer has a thickness of less than 100 nm.

20. The V-pit formation layer has a thickness exceeding 450 nm. The light-emitting diode according to claim 15, wherein the V-pits formed in the V-pit generation layer include V-pits with an entrance width exceeding 230 nm.

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