KR20170024461A - Light emitting diode cappable of emitting white light without phosphor and method of fabricating the same - Google Patents

Light emitting diode cappable of emitting white light without phosphor and method of fabricating the same Download PDF

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KR20170024461A
KR20170024461A KR1020150119765A KR20150119765A KR20170024461A KR 20170024461 A KR20170024461 A KR 20170024461A KR 1020150119765 A KR1020150119765 A KR 1020150119765A KR 20150119765 A KR20150119765 A KR 20150119765A KR 20170024461 A KR20170024461 A KR 20170024461A
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light
layer
type contact
contact layer
region
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KR1020150119765A
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Korean (ko)
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한창석
윤여진
이준희
김화목
최효식
이섬근
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서울바이오시스 주식회사
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Publication of KR20170024461A publication Critical patent/KR20170024461A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials
    • H01L33/504—Elements with two or more wavelength conversion materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/0004—Devices characterised by their operation
    • H01L33/0008—Devices characterised by their operation having p-n or hi-lo junctions
    • H01L33/0012—Devices characterised by their operation having p-n or hi-lo junctions p-i-n devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/12—Passive devices, e.g. 2 terminal devices
    • H01L2924/1204—Optical Diode
    • H01L2924/12041—LED

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Led Devices (AREA)

Abstract

Provided are a light emitting diode capable of emitting white light without a phosphor and a method for manufacturing the same. The light emitting diode according to an embodiment includes an n-type contact layer; a p-type contact layer; an active region interposed between the n-type contact layer and the p-type contact layer and emitting light of a main peak; and a gallium nitride based light absorbing-emitting layer which is located on the side of the n-type contact layer opposite to the active region and partially absorbs the light emitted from the active region to emit light of a yellow region. White light can be realized by using the light absorption-emitting layer without a phosphor.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a light emitting diode capable of emitting white light without a phosphor, and a method of manufacturing the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to an inorganic semiconductor light-emitting diode and a method of manufacturing the same, and more particularly, to a light-emitting diode capable of realizing white light without a phosphor by using an active region emitting near ultraviolet rays.

In general, gallium nitride based semiconductors are widely used in ultraviolet light, blue / green light emitting diodes or laser diodes as light sources for full color displays, traffic lights, general illumination and optical communication devices.

White light is required for various applications such as display and general illumination, and a light emitting diode can be used as a light source of white light. As a method for realizing white light, a method of combining blue or ultraviolet light emitting diodes and phosphors has been widely used. For example, white light can be realized by combining a blue light emitting diode and a yellow phosphor. However, since a phosphor is combined with a light emitting diode through a separate process after fabricating a light emitting diode chip, the process becomes complicated.

On the other hand, it is possible to provide light emitting diodes that emit white light without phosphors by disposing active regions that emit light of different wavelength regions in one chip. However, it is not easy to grow active regions having different compositions to have a good crystal quality on a single growth substrate. Furthermore, since these active regions are supplied with current through different current supply lines, the process of forming electrodes on the light emitting diode is very complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light emitting diode capable of realizing white light without a phosphor by a simple process.

Another object of the present invention is to provide a light emitting diode having an active region of good crystal quality.

According to an embodiment of the present invention, an n-type contact layer; a p-type contact layer; an active region interposed between the n-type contact layer and the p-type contact layer to emit light of a main peak; And a gallium nitride based light absorption-emitting layer which is located on the n-type contact layer side opposite to the active region and absorbs a part of light emitted from the active region to emit light in a yellow region .

According to another embodiment of the present invention, a gallium nitride-based light absorption-emitting layer is grown on a growth substrate, and an n-type contact layer, an active region and a p-type contact layer are grown on the light absorption- A method of fabricating a diode is provided. Here, the active region emits light of the main peak, and the light absorption-emitting layer absorbs part of the light emitted from the active region to emit light in the yellow region.

According to embodiments of the present invention, light in the yellow region can be emitted from the light absorbing-emitting layer by the light emitted from the active region, and white light can be realized using the light. Particularly, by emitting light having the main peak of the near ultraviolet region in the active region, white light can be realized by a combination of a part of the light of the main peak and the light of the yellow region.

1 is a cross-sectional view illustrating a light emitting diode according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a principle of light emission of a light emitting diode according to an embodiment of the present invention.
3 is an energy band diagram for explaining the light emission principle of a light emitting diode according to an embodiment of the present invention.
4 is a graph showing an emission spectrum of a light emitting diode according to the related art and a light emitting diode according to an embodiment of the present invention.
FIG. 5 is a photograph showing light emitted from a light emitting diode according to a conventional technique and a light emitting diode according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, and the like of constituent elements may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

A light emitting diode according to an embodiment of the present invention includes an n-type contact layer; a p-type contact layer; an active region interposed between the n-type contact layer and the p-type contact layer to emit light of a main peak; And a gallium nitride based light absorbing-emitting layer which is located on the side of the n-type contact layer opposite to the active region and absorbs part of the light emitted from the active region to emit light in the yellow region.

According to an embodiment of the present invention, light in the yellow region emitted from the gallium nitride-based light absorption-emitting layer can be used together with light emitted from the active region. Therefore, the light in the yellow region can be emitted without the phosphor. Further, the light absorption-emitting layer is not driven by electric energy but absorbs light generated in the active region and emits light of a new wavelength. Therefore, the light emitting diode according to the present embodiment can be driven by two electrodes, unlike a light emitting diode having a plurality of active regions which are individually driven individually, and the manufacturing process thereof is extremely simple.

The light emitting diode may emit white light by a combination of light in the yellow region and light in the blue region emitted from the light emitting diode. A part of the light of the main peak may include light in the blue region and the white light may be realized by a combination of light in the blue region and light in the yellow region.

In the embodiments of the present invention, the light in the yellow region is generated by recombination of deep level electrons of the light absorption-emitting layer. Refer to Applied Physics Letters 71 (22) (Appl. Phys. Lett., 71 (22), December 1, 1997) for the deep level of the gallium nitride based semiconductor layer. The recombination of deep level electrons is produced by defects in GaN-based crystals, and the prior art has proceeded in the direction of eliminating these defects. However, embodiments of the present invention use light in the yellow region generated by recombination of deep level electrons. Further, by setting the light of the main peak emitted from the active region as the light of the specific region, it is possible to realize white light which can be observed with the naked eye from the outside.

In some embodiments, the light of the main peak may have an emission peak within a range of 360 to 400 nm, and a part of the light of the main peak includes light of a blue region.

In some embodiments, the active region comprises a quantum well layer having an energy band gap in the range of 3.1 eV to 3.45 eV, and the light absorption-emitting layer has an energy band gap in the range of 2.95 eV to 3.65 eV have. Part of the light emitted from the active region is absorbed by the light absorption-emitting layer, and the recombination of deep level electrons may be caused by the absorbed light.

On the other hand, the active region may include a quantum well layer of AlxInyGazN (where 0? X <1, 0 <y <1, 0 <z <1), and the light absorption / emission layer may be AluInvGawN u < 1, 0? v <1, 0? w? 1). The composition ratio of Al, In and Ga is adjusted to control the energy bandgap of the active region and the light absorption-emitting layer.

Meanwhile, the n-type contact layer and the p-type contact layer each have an energy band gap wider than the energy band gap of the quantum well layer. Thus, light emitted from the active region can be prevented from being absorbed in the n-type contact layer or the p-type contact layer.

In some embodiments, the light absorption-emissive layer may have a higher Si doping concentration than the n-type contact layer. The Si doping concentration may be, for example, in the range of 1.5E19 / cm3 to 1E21 / cm3.

In some embodiments, the light emitting diode may further include a growth substrate. The light absorption-emitting layer is interposed between the growth substrate and the n-type contact layer. The growth substrate is not particularly limited as long as it is a substrate on which the gallium nitride based semiconductor layer can be grown. For example, a sapphire substrate or a patterned sapphire substrate. Furthermore, a buffer layer may be interposed between the growth substrate and the light absorption / emission layer.

A method for fabricating a light emitting diode according to another embodiment of the present invention includes growing a gallium nitride based light absorbing-emitting layer on a growth substrate, forming an n-type contact layer, an active region, and a p- Lt; / RTI &gt; layer. Here, the active region emits light of the main peak, and the light absorption-emitting layer absorbs part of the light emitted from the active region to emit light in the yellow region.

Since the light absorption-emitting layer is formed of a gallium nitride compound, it can be easily formed by using a conventional conventional gallium nitride semiconductor layer growth technique. Furthermore, the n-type contact layer, the active region and the p-type contact layer can also be grown as a gallium nitride-based semiconductor layer, so that the light absorption-emitting layer and these layers can be continuously grown without breaking the vacuum.

The light emitting diode may emit white light in combination with light in the blue region generated from the light emitting diode. Particularly, a part of the light of the main peak may include light of a blue region, and the white light may be realized by a combination of light of the blue region and light of the yellow region.

The light in the yellow region can be generated by recombination of deep level electrons of the light absorption-emitting layer.

In some embodiments, the light absorption-emissive layer can be grown at a temperature lower than the growth temperature of the n-type contact layer. For example, the n-type contact layer may be grown at a temperature of at least 1000 캜, while the light absorption-emissive layer may be grown at a temperature in the range of 700 캜 to 900 캜. The deep level can be generated by defects created therein by growing the light absorption-emissive layer at a relatively low temperature.

In yet other embodiments, the light absorption-emissive layer may have a higher Si doping concentration than the Si doping concentration in the n-type contact layer. The deep level can be generated by defects caused by overpoting of Si.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view illustrating a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 1, the light emitting diode includes a light absorption-emissive layer 27, an n-type contact layer 29, an active region 30, and a p-type contact layer 37. Further, the light emitting diode includes the growth substrate 21, the buffer layer 23, the n-type gallium nitride based semiconductor layer 25, the electronic block layer 35, the n-electrode 41 and the p-electrode 43 . In addition, although not shown in the drawings, the light emitting diodes may be added between the upper layers as needed.

The growth substrate 21 is a substrate for growing a gallium nitride based semiconductor layer, and is not particularly limited. For example, the growth substrate 21 may be a flat sapphire substrate or a patterned sapphire substrate (PSS), SiC, spinel, or the like. Here, although the light emitting diode is shown as including the growth wave 21, the growth substrate 21 may be removed from the light emitting diode.

The buffer layer 23 is a layer for relieving the occurrence of defects such as dislocation between the substrate 21 and the n-type contact layer 29. The buffer layer 23 has a thickness of about 1.5 占 퐉, for example, Can be grown on the growth substrate 21. Although not shown, the buffer layer 23 may include a nucleus layer formed on the growth substrate 21 to a thickness of about 25 nm at a low temperature of 400 to 600 DEG C with (Al, Ga) N. The buffer layer 23 may be grown using MOCVD. The GaN-based semiconductor layers described below may also be grown using MOCVD techniques as in the case of the buffer layer 23, unless otherwise specified.

The n-type gallium nitride based semiconductor layer 25 is grown on the buffer layer 23, and Si is doped as an impurity. The Si doping concentration is similar to or lower than the n-type contact layer 29. The n-type gallium nitride based semiconductor layer 25 can be grown at (Al, In, Ga) N at a temperature of 1000 캜 or higher.

The light absorption-emitting layer 27 is formed of a gallium nitride-based semiconductor layer. For example, the light absorption-emissive layer may be formed of AluInvGawN (with 0? U <1, 0? V <1, 0? W? 1). The light absorbing-emitting layer 27 has a number of deep level traps. The deep level traps in the gallium nitride based semiconductor layer correspond to the energy of light in the yellow region, for example, the deep level energy level in the GaN layer is about 2.2 eV. The thickness of the light absorbing-emitting layer 27 is not particularly limited, and may be, for example, in the range of 5 nm to 1 탆.

In one embodiment, the light absorbing-emitting layer 27 is formed on the growth substrate 21 Lt; RTI ID = 0.0 &gt; 700 C &lt; / RTI &gt; In particular, the light absorption-emissive layer 27 can be grown at a temperature lower than its growth temperature on a layer grown at a relatively high temperature, for example, an n-type gallium nitride-based semiconductor layer 25. By growing the gallium nitride-based semiconductor layer at a relatively low temperature, it is possible to cause defects in the layer to be grown, thereby increasing the deep level traps.

In yet another embodiment, the light absorption-emissive layer 27 may have an over-doped Si doping concentration. In this case, the light absorption-emissive layer 27 may be grown at a relatively low temperature as described above, but grown at a temperature similar to or higher than that of the n-type gallium nitride-based semiconductor layer 25. The Si doping concentration in the light absorption-emissive layer 27 is typically significantly higher than the concentration doped in the n-type contact layer 29, and may be in the range of, for example, 1.5E19 / cm3 to 1E21 / cm3.

The light absorption-emitting layer 27 has an energy band gap by the gallium nitride-based semiconductor layer, and also has a deep level. The light absorption-emitting layer 27 absorbs light of energy higher than the energy band gap of the gallium nitride-based semiconductor layer and emits light to the outside by recombination of deep-level electrons.

The n-type contact layer 29 is formed of an n-type impurity, for example, a gallium nitride-based semiconductor layer doped with Si, and may be formed to a thickness of about 1 to 3 m, for example. The n-type contact layer 29 has a bandgap wider than the energy band gap of the quantum well layer 33 of the active region 30 and may include, for example, a GaN, AlGaN layer or AlInGaN layer. The n-type contact layer 29 may be formed as a single layer or a multilayer, and may include a superlattice structure.

The n-type contact layer 29 is grown on the light absorption-emissive layer 27 at a temperature of about 1000 캜 or higher. On the other hand, since the light absorbing-emitting layer 27 includes a relatively high concentration of defects, it is preferable that light is emitted on the light absorbing-emitting layer 27 at a relatively high temperature of 1000 캜 or higher before growing the n-type contact layer 29 A gallium nitride-based crystalline recovery layer (not shown) having the same or similar composition as the absorption-emitting layer 27 may be grown.

The active region (30) includes a barrier layer (31) and a quantum well layer (33). Although a single quantum well layer 33 is shown in the figure as a single quantum well structure, the active region 30 has multiple quantum wells 33, including barrier layers 31 and alternately stacked barrier layers 31, It may have a well structure. The quantum well layer 33 may emit light having a main peak in the near ultraviolet to short wavelength visible light range of 360 nm to 400 nm. The quantum well layer 33 may be formed of AlxInyGazN (where 0? X <1, 0 <y <1, 0 <z <1) and may be formed of GaN, InGaN or AlInGaN, for example. In addition, the quantum well layer 33 may be formed to a thickness of 20 to 70 angstroms. The composition and thickness of Al, In, Ga can be adjusted so that the quantum well layer 33 has an energy bandgap in the range of 3.1 eV to 3.45 eV.

Particularly, a part of the light emitted from the active region 30 has energy larger than the energy band gap of the light absorption-emitting layer 27. For example, when the quantum well layer 33 has the energy band gap, the light absorption-emitting layer may have an energy band gap within the range of 2.95 eV to 3.65 eV. Accordingly, a part of the light emitted from the active region 30 can be absorbed by the light absorption-emitting layer 27 to generate free electrons. Some of these free electrons will be trapped in the deep level trap and recombine with the holes to produce light in the yellow region.

The barrier layers 31 may be formed of a gallium nitride based semiconductor layer having a larger bandgap than the well layer 33, for example, GaN, InGaN, AlGaN, or AlInGaN. In particular, the barrier layers 31 can be formed of AlInGaN, which can mitigate lattice mismatch between the well layer 33 and the barrier layer 31 by including In.

The p-type contact layer 37 is located on the active region 30. On the other hand, the electronic block layer 35 may be located between the active region 30 and the p-type contact layer 37. The electron blocking layer 35 may be formed of AlGaN or AlInGaN. When formed of AlInGaN, lattice mismatch with the active region 30 can be further mitigated. At this time, the electron blocking layer 35 has an Al content higher than that of the barrier layer 31. The electron blocking layer 35 may be doped with a p-type impurity, such as Mg, but may not intentionally doping impurities. The electron blocking layer 35 may be formed to a thickness of about 15 nm.

The p-type contact layer 37 may be formed of a Mg-doped GaN layer, an AlGaN layer, or an AlInGaN layer, and the thickness may be 100 nm. The p-type contact layer 37 may be formed of a single layer, but not limited thereto, and may be formed of multiple layers. Furthermore, the p-type contact layer 37 is not limited to the gallium nitride-based semiconductor layer but may be formed of another kind of compound semiconductor.

On the other hand, the n-electrode 41 and the p-electrode 43 are in electrical contact with the n-type contact layer 29 and the p-type contact layer 37, respectively. These electrodes 41 and 43 are formed to supply electric current to the active region 30 from the outside. It should be noted here that the light absorbing-emitting layer 27 is disposed outside the path of the current supplied from these electrodes 41 and 43. That is, the light absorbing-emitting layer 27 is located on the side of the n-type contact layer 29 opposite to the active region 30. A conventional light emitting diode having a plurality of active regions needs to supply current to each active region. However, the light emitting diode according to the embodiments of the present invention does not need to supply current to the light absorbing-emitting layer 27, and therefore, the electrode structure is extremely simple.

2 and 3 are a cross-sectional view and an energy band diagram for explaining the light emission principle of a light emitting diode according to an embodiment of the present invention, respectively.

Referring to FIG. 2, when current is supplied through the n-electrode 41 and the p-electrode 43, light of the main peak is generated in the quantum well layer 33 in the active region 30. A part L1 of the light is emitted directly to the outside of the light emitting diode while the other part L2 travels toward the light absorbing and emitting layer 27. [ A part of the light L2 directed toward the light absorbing-emitting layer 27 is absorbed by the light absorbing-emitting layer 27, and the rest will be emitted to the outside although not shown. On the other hand, the light absorbing-emitting layer 27 absorbs a part of the light L2, and then generates light L3 in the yellow region. And the light L3 is emitted to the outside.

Accordingly, outside of the light emitting diode, light generated by the active region 30 and combined with the light L1 emitted to the outside and the light L3 generated from the light absorption-emitting layer 27 are observed. Here, the light L1 may contain light in the blue region by the spectrum distribution, and the white light is realized by the combination of the light in the blue region and the light L3 in the yellow region.

The process of generating light in the yellow region according to the embodiments of the present invention will be described with reference to the energy band diagram of FIG. Here, the energy band diagram of Fig. 3 shows the energy band gap Eg of the light absorption-emissive layer 27. Fig.

Referring to Fig. 3, a part (L2) of light generated in the active region 30 is absorbed in the light absorption-emitting layer 27. Fig. L2 excites the electrons below the valence band to generate free electrons. A part of the free electrons will recombine with the holes to emit light corresponding to the energy band gap Eg of the light absorption-emitting layer 27 to the outside. However, if the light absorbing-emitting layer 27 has a significant amount of deep level traps, a significant number of free electrons are trapped at the deep level indicated by the dashed line, then recombined with the holes to form light L3 in the yellow region. . Refer to Applied Physics Letters 71 (22) (Appl. Phys. Lett., 71 (22), December 1, 1997) for light in the yellow region emitted by recombination of deep level electrons in the gallium nitride based semiconductor layer .

FIG. 4 is a graph showing an emission spectrum of a light emitting diode according to an embodiment of the present invention, and FIG. 4 (b) is a graph showing the spectrum of the light emitting diode according to the related art, 1 shows a spectrum of a light emitting diode according to an embodiment of the present invention.

Here, the light emitting diode according to the related art is manufactured to emit light having a main peak of about 375 nm without the light absorbing-emitting layer 27, and the light emitting diode according to an embodiment of the present invention includes the light absorbing- ). The light emitting diode according to the prior art and the light emitting diode according to the embodiment of the present invention were fabricated under the same conditions except for the presence of the light absorption / emission layer 27. On the other hand, the quantum well layer is made of InGaN and the light absorption-emitting layer 27 is made of GaN layer.

Referring to FIGS. 4A and 4B, in the light emitting diode b according to the embodiment of the present invention, light is detected in the yellow region Y, The spectrum is scarcely detected in the region. Accordingly, the light emitting diode (b) according to the embodiment of the present invention can realize white light by combining light (B) in a blue region of 400 to 450 nm and light (Y) in a yellow region, It can be seen that only the light B in the blue region will be observed. This can be confirmed practically through the photograph of FIG.

4A and 4B, when the intensity of light in the region B near 450 nm is examined, it can be seen that the intensity of the light emitting diode according to the prior art is higher than that of the light emitting Which is higher than the intensity of the diode. That is, by applying the light absorbing-emitting layer 27, the crystal quality of the active region 30 of the light emitting diode according to an embodiment of the present invention is improved as compared with the prior art light emitting diode.

FIG. 5 is a photograph showing light emitted from a light emitting diode according to an embodiment of the present invention, and FIG. 5 (a) is a photograph of light emitting diode of FIG. 4 (a) And FIG. 5 (b) is a photograph of the light emitting diode of FIG. 4 (b) according to an embodiment of the present invention.

Referring to FIGS. 5 (a) and 5 (b), the light emitting diode according to the related art emits light in the blue region because the light Y in the yellow region is not emitted. On the other hand, in the light emitting diode according to the embodiment of the present invention, the light Y in the yellow region is emitted together with the light B in the blue region.

According to embodiments of the present invention, it is possible to provide a light emitting diode in which white light is observed from the outside by introducing a light absorption-emitting layer 27 into a light emitting diode that emits light in the near ultraviolet or short wavelength visible region. White light was observed through the CIE color coordinates, and it was confirmed that white light of 3000K or more was emitted even when CCT (color correlated temperature) measurement was performed.

Such a light emitting diode may be used for various applications using white light. Further, since the light in the near ultraviolet or short wavelength visible region has a short wavelength, it is difficult to visually observe it from the outside. By emitting light (Y) in the yellow region to the outside by using the light absorption- It may indicate that the visible region light emitting diode is operating properly.

Further, by applying the light absorbing-emitting layer 27, it is possible to improve the crystal quality of the active region, and thus it is possible to determine whether or not the light emitting diode is defective by the presence or absence of white light.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the present invention is not limited to the above-described embodiments.

21 growth substrate
23 buffer layer
25 n-type gallium nitride-based semiconductor layer
27 light absorbing-emitting layer (27)
29 n-type contact layer
30 active area
31 barrier layer
33 quantum well layer
35 electronic block layer
37 p-type contact layer
41 n- electrode
43 p-electrode
e electron
h hole

Claims (17)

an n-type contact layer;
a p-type contact layer;
an active region interposed between the n-type contact layer and the p-type contact layer to emit light of a main peak; And
And a gallium nitride based light absorbing-emitting layer located on the side of the n-type contact layer opposite to the active region and absorbing part of light emitted from the active region to emit light in a yellow region. The method according to claim 1,
Wherein the light in the yellow region is combined with the light in the blue region generated from the light emitting diode to emit white light. The method of claim 2,
A part of the light of the main peak includes light in the blue region,
Wherein the white light is realized by a combination of the light in the blue region and the light in the yellow region. The method of claim 3,
Wherein light in the yellow region is generated by recombination of deep level electrons of the light absorption-emitting layer. The method according to claim 1,
Wherein the main peak light has an emission peak within a range of 360 nm to 400 nm,
And a part of the light of the main peak includes light in the blue region. The method of claim 5,
Wherein the active region comprises a quantum well layer having an energy band gap in the range of 3.1 eV to 3.45 eV,
Wherein the light absorption-emitting layer has an energy band gap within a range of 2.95 eV to 3.65 eV. The method of claim 5,
Wherein the active region comprises a quantum well layer of AlxInyGazN (0? X <1, 0 <y <1, 0 <z <
Emitting layer is formed of AluInvGawN (with 0? U <1, 0? V <1, 0? W? 1). The method of claim 7,
Wherein the n-type contact layer and the p-type contact layer each have an energy band gap wider than the energy band gap of the quantum well layer. The method according to claim 1,
Wherein the light absorption-emitting layer has a higher Si doping concentration than the n-type contact layer. The method according to claim 1,
Further comprising a growth substrate,
Emitting layer is interposed between the growth substrate and the n-type contact layer. The method of claim 10,
And a buffer layer interposed between the growth substrate and the light absorption-emitting layer. A gallium nitride based light absorption-emitting layer is grown on a growth substrate,
And growing an n-type contact layer, an active region and a p-type contact layer on the light absorption-emitting layer,
Wherein the active region emits light of a main peak and the light absorption-emitting layer absorbs a portion of the light emitted from the active region to emit light in a yellow region. The method of claim 12,
Wherein the light emitting diode emits white light. 14. The method of claim 13,
A part of the light of the main peak includes light in the blue region,
Wherein the white light is realized by a combination of the light of the blue region and the light of the yellow region. 15. The method of claim 14,
Wherein the light in the yellow region is generated by recombination of deep level electrons of the light absorbing-emitting layer. 16. The method of claim 15,
Emitting layer is grown at a temperature lower than the growth temperature of the n-type contact layer. 16. The method of claim 15,
Wherein the light absorption-emitting layer has a Si doping concentration higher than the Si doping concentration in the n-type contact layer.
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