KR20150011890A

KR20150011890A - Light emitting device

Info

Publication number: KR20150011890A
Application number: KR1020130087050A
Authority: KR
Inventors: 황정현; 강고운; 백지현; 이정식; 한대섭
Original assignee: 엘지이노텍 주식회사
Priority date: 2013-07-24
Filing date: 2013-07-24
Publication date: 2015-02-03

Abstract

A light emitting device according to an embodiment includes a first semiconductor layer, a second semiconductor layer, an active layer between the first semiconductor layer and the second semiconductor layer, and a middle layer arranged between the active layer and the second semiconductor layer. The middle layer includes InGaN doped with P-type dopant, a first layer adjacent to the active layer, and a second layer adjacent to the second semiconductor layer. The doping concentration of the dopant of the first layer may be lower than the doping concentration of the dopant of the second layer.

Description

[0001]

An embodiment relates to a light emitting element.

As a typical example of a light emitting device, a light emitting diode (LED) is a device for converting an electric signal into an infrared ray, a visible ray, or a light using the characteristics of a compound semiconductor, and is used for various devices such as household appliances, remote controllers, Automation equipment, and the like, and the use area of LEDs is gradually widening.

In general, miniaturized LEDs are made of a surface mounting device for mounting directly on a PCB (Printed Circuit Board) substrate, and an LED lamp used as a display device is also being developed as a surface mounting device type . Such a surface mount device can replace a conventional simple lighting lamp, which is used for a lighting indicator for various colors, a character indicator, an image indicator, and the like.

As the use area of the LED is widened as described above, it is important to increase the luminance of the LED as the brightness required for a lamp used in daily life and a lamp for a structural signal is increased.

The embodiment is to provide a light emitting device that increases efficiency of hole injection and increases efficiency.

The light emitting device according to the embodiment includes a first semiconductor layer, a second semiconductor layer, an active layer disposed between the first semiconductor layer and the second semiconductor layer, and an intermediate layer disposed between the active layer and the second semiconductor layer Wherein the intermediate layer comprises InGaN doped with a p-type dopant and includes a first layer adjacent to the active layer and a second layer adjacent to the second semiconductor layer, the doping concentration of the dopant of the first layer being May be lower than the doping concentration of the dopant of the second layer.

In the light emitting device according to the embodiment, since the intermediate layer is disposed between the second semiconductor layer and the active layer, the piezoelectric polarization phenomenon is improved and the recombination probability of electrons and holes is increased, and the luminous efficiency can be improved.

The doping concentration of the p-type dopant in the first layer adjacent to the active layer is made lower than the doping concentration of the p-type dopant in the second layer so as to reduce the amount of the p-type dopant diffused into the active layer, .

Further, in the embodiment, the luminous efficiency is improved and the operating voltage of the light emitting element is also decreased.

1 is a cross-sectional view illustrating a light emitting device according to an embodiment.
2 is an enlarged view of a portion of FIG.
3 is an energy band diagram of the light emitting device according to the embodiment of FIG.
4 is a cross-sectional view illustrating a light emitting device according to another embodiment.
FIG. 5 is a diagram illustrating an energy band diagram of a light emitting device according to the embodiment of FIG.
6 is a cross-sectional view illustrating a light emitting device package including the light emitting device according to the embodiment.
7 is an exploded perspective view of a display device including a light emitting device according to an embodiment.
8 is a cross-sectional view of the display device of Fig.
9 is an exploded perspective view of a lighting device including a light emitting device according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size and area of each component do not entirely reflect actual size or area.

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

FIG. 1 is a cross-sectional view showing a light emitting device according to an embodiment, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is an energy band diagram of a light emitting device according to the embodiment of FIG.

1, the light emitting device 100 may include a substrate 110 and a light emitting structure disposed on the substrate 110. The light emitting structure may include a first semiconductor layer 120, an active layer 130, A first semiconductor layer 180 and a second semiconductor layer 150.

The substrate 110 may be formed of any material having optical transparency, for example, sapphire (Al ₂ O ₃ ), GaN, ZnO, or AlO, but is not limited thereto. In addition, the substrate 110 may be formed of a carrier wafer, a material suitable for semiconductor material growth. A SiC substrate having a higher thermal conductivity than a sapphire (Al ₂ O ₃ ) substrate or an SiC substrate including Si, GaAs, GaP, InP, Ga ₂ O ₃ can be used.

On the other hand, a concavo-convex structure may be provided on the upper surface of the substrate 110 to enhance light extraction efficiency. The substrate 110 referred to herein may or may not have a concave-convex structure.

A buffer layer (not shown) may be disposed on the substrate 110 to mitigate lattice mismatch between the substrate 110 and the first semiconductor layer 120 and to facilitate growth of the semiconductor layer. The buffer layer (not shown) can be formed in a low-temperature atmosphere and can be made of a material that can alleviate the difference in lattice constant between the semiconductor layer and the substrate 110. But are not limited to, materials such as, for example, GaN, InN, AlN, AlInN, InGaN, AlGaN, and InAlGaN. .

A buffer layer (not shown) may be grown on the substrate 110 as a single crystal, and a buffer layer (not shown) grown by a single crystal may improve the crystallinity of the first semiconductor layer 120 grown on the buffer layer have.

A light emitting structure 160 including a first semiconductor layer 120, an active layer 130, and a second semiconductor layer 150 may be formed on a buffer layer (not shown).

The first semiconductor layer 120 may be located on a buffer layer (not shown). The first semiconductor layer 120 may be formed of a semiconductor compound and may be doped with a first conductive dopant. For example, the first semiconductor layer 120 may be formed of an n-type semiconductor layer and may provide electrons to the active layer 130. The first semiconductor layer 120 may be a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN and AlInN, and n-type dopants such as Si, Ge, Sn, Se and Te can be doped.

Further, the semiconductor layer 120 may further include an undoped semiconductor layer (not shown), but the present invention is not limited thereto. The un-doped semiconductor layer is a layer formed for improving the crystallinity of the first semiconductor layer 120 and has a lower electrical conductivity than the first semiconductor layer 120 without doping the n-type dopant. May be the same as the semiconductor layer 120.

The active layer 130 may be formed on the first semiconductor layer 120. The active layer 130 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of Group 3-V group elements.

When the active layer 130 has a quantum well structure, for example, a well layer having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) And a barrier layer having a composition formula of In _a Al _b Ga _1-ab N (0? A? 1, 0? B? 1, 0? A + b? 1). The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

In addition, when the active layer 130 has a multiple quantum well structure, each well layer (not shown) may have a different In content and different band gaps, which will be described later with reference to FIG.

A conductive clad layer (not shown) may be formed on and / or below the active layer 130. The conductive clad layer (not shown) may be formed of a semiconductor and may have a band gap larger than that of the active layer 130. For example, the conductive clad layer (not shown) may be formed including AlGaN,

The second semiconductor layer 150 may be formed of a semiconductor compound to inject holes into the active layer 130 and may be doped with a second conductive dopant. For example, the second semiconductor layer 140 may be implemented as a p-type semiconductor layer. The second semiconductor layer 150 may be a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN and AlInN, and a p-type dopant such as Mg, Zn, Ca, Sr and Ba may be doped.

An electron blocking layer 140 may be formed between the active layer 130 and the second semiconductor layer 150. The electron blocking layer 140 may be formed from the first semiconductor layer 120 to the active layer 130 Can be prevented from flowing to the second semiconductor layer 150 without being recombined in the active layer 130. [ The electron blocking layer 140 has a band gap relatively larger than that of the active layer 130 so that electrons injected from the first semiconductor layer 120 are injected into the second semiconductor layer 150 without being recombined in the active layer 130. [ Can be prevented. Accordingly, the probability of recombination of electrons and holes in the active layer 130 can be increased and the leakage current can be prevented.

The intermediate layer 180 may be disposed between the active layer 130 and the second semiconductor layer 150. The intermediate layer 180 may have a larger lattice constant than the second semiconductor layer 150.

The first semiconductor layer 120, the active layer 130, the intermediate layer 180, and the second semiconductor layer 150 may be formed by, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD) (Chemical Vapor Deposition), plasma enhanced chemical vapor deposition (PECVD), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE), sputtering, etc. But the present invention is not limited thereto.

In addition, the doping concentration of the conductive dopant in the first semiconductor layer 120 and the second semiconductor layer 150 can be uniformly or nonuniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the invention is not limited thereto.

The first semiconductor layer 120 may be a p-type semiconductor layer, the second semiconductor layer 150 may be an n-type semiconductor layer, and the second semiconductor layer 150 A third semiconductor layer (not shown) including an n-type or p-type semiconductor layer which is opposite to the polarity of the n-type or p-type semiconductor layer may be formed. Accordingly, the light emitting device 100 may have at least one of np, pn, npn, and pnp junction structures.

A light-transmitting electrode layer 170 may be formed on the second semiconductor layer 150. The transparent electrode layer 170 is ITO, IZO (In-ZnO) , GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrO x, RuO x , RuO _x / ITO, Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO. Accordingly, the light generated in the active layer 130 can be diverted to the outside, and formed on the whole or a part of the outer side of the second semiconductor layer 150, thereby preventing current clustering.

A first electrode 172 electrically connected to the first semiconductor layer 120 may be disposed on the first semiconductor layer 120. For example, the active layer 130 and the second semiconductor layer 150 may be partially removed to expose a portion of the first semiconductor layer 120, and a first electrode (not shown) may be formed on the exposed first semiconductor layer 120, 172 may be formed. That is, the first semiconductor layer 120 includes a top surface facing the active layer 130 and a bottom surface facing the substrate 110, and an upper surface includes a region exposed at least one region, As shown in FIG. However, the present invention is not limited thereto.

Meanwhile, a method of exposing a part of the first semiconductor layer 120 may use a predetermined etching method, but is not limited thereto. The etching method may be a wet etching method or a dry etching method.

Also, a second electrode 174 may be formed on the second semiconductor layer 150.

The first and second electrodes 172 and 174 may be formed of a conductive material such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, , A metal selected from Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, and WTi or an alloy thereof and may be formed as a single layer or a multilayer .

2, the active layer 130 of the light emitting device 100 may have a multiple quantum well structure, and thus the active layer 130 may include first to third well layers Q1, Q2, and Q3, And a third barrier layer (B1, B2, B3).

The first through third well layers Q1, Q2 and Q3 and the first through third barrier layers B1, B2 and B3 may have a structure in which they are alternately stacked as shown in FIG.

In FIG. 2, first through third well layers Q1, Q2 and Q3 and first through third barrier layers B1, B2 and B3 are formed and first through third well layers Q1 and Q2 Q2 and Q3 and barrier layers B1, B2 and B3 are alternately stacked, but not limited thereto, and the well layers Q1, Q2 and Q3 and the barrier layers B1, B2, B3 may be formed to have any number, and the arrangement may also have any arrangement. In addition, as described above, the composition ratio, band gap, and thickness of the material forming each of the well layers Q1, Q2, and Q3 and the barrier layers B1, B2, and B3 may be different from each other, 2 as shown in Fig.

The barrier layers B1, B2, and B3 may have band gap energies greater than those of the well layers Q1, Q2, and Q3. For example, the barrier layers B1, B2, and B3 may include GaN, and the well layers Q1, Q2, and Q3 may include InGaN.

Referring again to FIGS. 1 and 2, an intermediate layer 180 may be disposed between the active layer 130 and the second semiconductor layer 150. The intermediate layer 180 may have a larger lattice constant than the second semiconductor layer 150.

The intermediate layer 180 may include, for example, InGaN, but is not limited thereto. The intermediate layer 180 serves to improve the injection efficiency of holes from the second semiconductor layer 150 to the active layer 130 by alleviating the piezoelectric polarization effect between the active layer 130 and the second semiconductor layer 150.

The intermediate layer 180 may be formed to a thickness of 2 nm to 6 nm. When the thickness of the intermediate layer 180 is formed to be thinner than 2 nm, piezoelectric polarization of the second semiconductor layer 150 and the active layer 130 can not be mitigated. If the thickness of the intermediate layer is thicker than 6 nm, The hole injection efficiency from the layer 150 to the active layer 130 may be reduced. However, the present invention is not limited thereto.

In the case where the intermediate layer 180 includes InGaN, if the composition ratio of In is larger than 6%, the band gap becomes small, and thus the hole serving as a hole for supplying the active layer 130 from the second semiconductor layer 150 If the composition ratio of In is less than 2% $, the bandgap is increased, so that the injection efficiency of holes supplied to the active layer 130 from the second semiconductor layer 150 can be reduced. Therefore, the band gap energy of the intermediate layer 180 may be larger than the band gap energy of the well layers Q1, Q2, and Q3, and may be smaller than the band gap energy of the second semiconductor layer 150. [

The intermediate layer 180 may be doped with a p-type dopant, and the p-type dopant may include any one of Mg, Zn, Ca, Sr, and Ba. For example, the intermediate layer 180 may be doped with Mg (magnesium).

Specifically, the intermediate layer 180 may have a structure in which a plurality of layers are stacked, and a layer adjacent to the active layer 130 may have a doping concentration of a lower dopant than a layer adjacent to the second semiconductor layer 150.

For example, the intermediate layer 180 may include a first layer 181 adjacent to the active layer 130 and a second layer 182 adjacent to the second semiconductor layer 150, and the first layer 181, The doping concentration of the dopant of the second layer 182 may be lower than the doping concentration of the dopant of the second layer 182.

Doping the intermediate layer 180 with the p-type dopant improves the efficiency of injecting holes injected from the second semiconductor layer 150 into the intermediate layer 180. The p-type dopant may be diffused into the adjacent active layer 130 Diffusion phenomenon occurs. The p-type dopant diffused into the active layer 130 lowers the luminous intensity of the light emitting device.

Therefore, when the doping concentration of the p-type dopant of the first layer 181 adjacent to the active layer 130 is lower than the doping concentration of the p-type dopant of the second layer 182, the p-type dopant diffused into the active layer 130 The effect of improving the injection efficiency of holes injected into the active layer 130 from the second semiconductor layer 150 without decreasing the luminous intensity of the light emitting device by reducing the amount of electrons. That is, the band gap energy of the second layer 182 can be made larger than the band gap energy of the first layer 181.

The intermediate layer may be composed of two or more layers but is not limited thereto.

As a result, the light emitting device of the embodiment has an effect of improving the luminous efficiency without lowering the luminous intensity. Further, the operating voltage of the light emitting element is also reduced.

For example, when the intermediate layer 180 is doped with Mg as a p-type dopant, the doping concentration of the first layer 181 may be between 1E18 and 1E19 cm- ³ , and the doping concentration of the second layer 182 may be between the first May be greater than 5E18 to 5E19 cm <" ³ > If the doping concentration of Mg is too low, the effect of improving the injection efficiency of holes injected into the active layer 130 from the second semiconductor layer 150 is not large. If the doping concentration of Mg is too high, The amount of Mg diffused into the light emitting layer 130 increases and the luminous intensity of the light emitting device decreases.

The band gap energy of the first layer 181 is greater than the band gap energy of the well layers Q1, Q2 and Q3 and the band gap energy of the barrier layers B1, B2 and B3 and the band gap energy of the second semiconductor layer 150 Can be small. If the band gap of the intermediate layer 180 is too low, it may serve to confine the holes supplied to the active layer 130 from the second semiconductor layer 150. If the band gap energy is too large, the second semiconductor layer 150 The injection efficiency of the holes supplied to the active layer 130 can be reduced. Piezoelectric polarizations may be generated in the semiconductor layer due to the stress caused by the difference in lattice constant and the orientation between the semiconductor layers. Since the semiconductor material forming the light emitting element has a large value of the piezoelectric coefficient, it can cause a very large polarization even with a small strain. The electric field induced by the two polarizations changes the energy band structure of the light emitting device and distorts the distribution of electrons and holes accordingly. This effect is called a quantum confined stark effect (QCSE), which causes a low internal quantum efficiency in a light emitting device that emits light due to the recombination of electrons and holes, and causes a red shift in the emission spectrum The electrical and optical characteristics of the device may be adversely affected. Particularly, the above-mentioned strain increases the polarization effect to further enhance the internal electric field, and accordingly, the band is bent according to the electric field to form a triangle potential well (the second semiconductor layer 150 and the active layer 130 , And a shape in which electrons or holes are concentrated on the triangle potential well may occur. Therefore, the recombination rate of electrons and holes may be lowered. That is, there is a problem that the hole injection efficiency from the second semiconductor layer 150 to the active layer 130 is lowered.

On the other hand, crystal defects due to the difference in lattice constant between the substrate 110 and the light emitting structure formed on the substrate 110 tend to increase with the growth direction, The semiconductor layer 150 may have the largest crystal defects. Considering the fact that the hole mobility is lower than the electron mobility, the decrease in the hole injection efficiency due to the lowering of the crystallinity of the second semiconductor layer 150 is caused by the light emitting efficiency of the light emitting element 100 Can be reduced.

If the intermediate layer 180 is disposed between the active layer 130 and the second semiconductor layer 150 and the intermediate layer 180 has a large lattice constant as in the embodiment described above, generation of the triangle potential well described above is reduced Therefore, the recombination rate of electrons and holes can be increased, and the luminous efficiency of the luminous means 100 can be improved. In addition, the holes that have escaped from the second semiconductor layer 150 have high energy and can pass through the triangle potential well. Therefore, the luminous efficiency of the luminous means 100 can be improved.

FIG. 4 is a cross-sectional view illustrating a light emitting device according to another embodiment, and FIG. 5 is a diagram illustrating an energy band diagram of a light emitting device according to the embodiment of FIG.

4 and 5, the light emitting device 100A of the embodiment has an electron blocking layer 140 (see FIG. 1) between the intermediate layer 180 and the second semiconductor layer 150 as compared with the light emitting device 100 of the embodiment of FIG. ). &Lt; / RTI >

The electron blocking layer 140 blocks the flow of electrons supplied from the first semiconductor layer 120 toward the second semiconductor layer 150 and increases the probability of recombination of electrons and holes in the active layer 130 .

The electron blocking layer 140 may have a larger bandgap than the bandgap of the barrier layers B1, B2 and B3 included in the active layer 130 and the second semiconductor layer 150. For example, AlGaN or InAlGaN , And may be doped with a p-type dopant, but the present invention is not limited thereto.

At this time, the intermediate layer 180 may have a larger lattice constant than the electron blocking layer 140 and the second semiconductor layer 150.

6 is a cross-sectional view illustrating a light emitting device package including the light emitting device according to the embodiment.

6, the light emitting device package 300 includes a body 310 having a cavity, a light source 320 mounted on a cavity of the body 310, and an encapsulant 350 filled in the cavity 310 can do.

The body 310 may be made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photo sensitive glass (PSG), polyamide 9T (SPS), a metal material, sapphire (Al2O3), beryllium oxide (BeO), a printed circuit board (PCB), and ceramics. The body 310 may be formed by injection molding, etching, or the like, but is not limited thereto.

The light source unit 320 may be disposed on the bottom surface of the body 310. For example, the light source unit 320 may be any one of the light emitting devices illustrated in FIGS. The light emitting device may be, for example, a colored light emitting device that emits light such as red, green, blue, or white, or a UV (Ultra Violet) light emitting device that emits ultraviolet light. In addition, one or more light emitting elements can be mounted.

The body 310 may include a first electrode 330 and a second electrode 340. The first electrode 330 and the second electrode 340 may be electrically connected to the light source 320 to supply power to the light source 320.

In addition, the first electrode 330 and the second electrode 340 are electrically separated from each other. The first electrode 330 and the second electrode 340 can reflect the light generated from the light source unit 320 to increase the light efficiency. Further, To the outside.

6 illustrates that both the first electrode 330 and the second electrode 340 are bonded to the light source 320 by the wire 360. However, the present invention is not limited thereto, Any one of the electrode 330 and the second electrode 340 may be bonded to the light source 320 by the wire 360 and may be electrically connected to the light source 320 without the wire 360 by the flip- have.

The first electrode 330 and the second electrode 340 may be formed of a metal material such as titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), tantalum Ta, Pt, Sn, Ag, P, Al, Pd, Co, Si, Ge, Ge), hafnium (Hf), ruthenium (Ru), and iron (Fe). The first electrode 330 and the second electrode 340 may have a single-layer structure or a multi-layer structure, but the present invention is not limited thereto.

The encapsulant 350 may be filled in the cavity and may include a phosphor (not shown). The encapsulant 350 may be formed of a transparent silicone, epoxy, or other resin material, and may be formed in such a manner that the encapsulant 350 is filled in the cavity and then cured by UV or thermal curing.

The phosphor (not shown) may be selected according to the wavelength of the light emitted from the light source unit 320 so that the light emitting device package 300 may emit white light.

The fluorescent material (not shown) included in the encapsulant 350 may be a blue light emitting phosphor, a blue light emitting fluorescent material, a green light emitting fluorescent material, a yellow green light emitting fluorescent material, a yellow light emitting fluorescent material, , An orange light-emitting fluorescent substance, and a red light-emitting fluorescent substance may be applied.

That is, the phosphor (not shown) may be excited by the light having the first light emitted from the light source 320 to generate the second light. For example, when the light source 320 is a blue light emitting diode and the phosphor (not shown) is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light emitted from the blue light emitting diode and blue The light emitting device package 300 can provide white light as yellow light generated by excitation by light is mixed.

The light emitting device according to the embodiment can be applied to an illumination system. The lighting system includes a structure in which a plurality of light emitting elements are arrayed and includes a display device shown in Figs. 7 and 8, a lighting device shown in Fig. 9, and may include a lighting lamp, a traffic light, a vehicle headlight, have.

7 is an exploded perspective view of a display device having a light emitting device according to an embodiment.

7, a display device 1000 according to an embodiment includes a light guide plate 1041, a light source module 1031 for providing light to the light guide plate 1041, and a reflection member 1022 An optical sheet 1051 on the light guide plate 1041 and a display panel 1061 on the optical sheet 1051 and the light guide plate 1041 and the light source module 1031 and the reflection member 1022 But is not limited to, a bottom cover 1011.

The bottom cover 1011, the reflective sheet 1022, the light guide plate 1041, and the optical sheet 1051 can be defined as a light unit 1050.

The light guide plate 1041 serves to diffuse light into a surface light source. The light guide plate 1041 may be made of a transparent material, for example, acrylic resin such as polymethylmethacrylate (PET), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphtha late Resin. &Lt; / RTI >

The light source module 1031 provides light to at least one side of the light guide plate 1041, and ultimately acts as a light source of the display device.

The light source module 1031 includes at least one light source module 1031 and may directly or indirectly provide light from one side of the light guide plate 1041. The light source module 1031 includes a substrate 1033 and a light emitting device 1035 according to the embodiment described above and the light emitting devices 1035 may be arrayed at a predetermined interval on the substrate 1033 .

The substrate 1033 may be a printed circuit board (PCB) including a circuit pattern (not shown). However, the substrate 1033 may include not only a general PCB, but also a metal core PCB (MCPCB), a flexible PCB (FPCB), and the like. When the light emitting element 1035 is mounted on the side surface of the bottom cover 1011 or on the heat radiation plate, the substrate 1033 can be removed. Here, a part of the heat radiating plate may be in contact with the upper surface of the bottom cover 1011.

The plurality of light emitting devices 1035 may be mounted on the substrate 1033 such that the light emitting surface is spaced apart from the light guiding plate 1041 by a predetermined distance. However, the present invention is not limited thereto. The light emitting device 1035 may directly or indirectly provide light to the light-incident portion, which is one surface of the light guide plate 1041, but the present invention is not limited thereto.

The reflective member 1022 may be disposed under the light guide plate 1041. The reflection member 1022 reflects the light incident on the lower surface of the light guide plate 1041 so as to face upward, thereby improving the brightness of the light unit 1050. The reflective member 1022 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto. The reflective member 1022 may be an upper surface of the bottom cover 1011, but is not limited thereto.

The bottom cover 1011 may house the light guide plate 1041, the light source module 1031, the reflective member 1022, and the like. To this end, the bottom cover 1011 may be provided with a housing portion 1012 having a box-like shape with an opened upper surface, but the present invention is not limited thereto. The bottom cover 1011 may be coupled to the top cover, but is not limited thereto.

The bottom cover 1011 may be formed of a metal material or a resin material, and may be manufactured using a process such as press molding or extrusion molding. In addition, the bottom cover 1011 may include a metal or a non-metal material having good thermal conductivity, but the present invention is not limited thereto.

The display panel 1061 is, for example, an LCD panel, including first and second transparent substrates facing each other, and a liquid crystal layer interposed between the first and second substrates. A polarizing plate may be attached to at least one surface of the display panel 1061, but the present invention is not limited thereto. The display panel 1061 displays information by light passing through the optical sheet 1051. Such a display device 1000 can be applied to various types of portable terminals, monitors of notebook computers, monitors of laptop computers, televisions, and the like.

The optical sheet 1051 is disposed between the display panel 1061 and the light guide plate 1041 and includes at least one light-transmitting sheet. The optical sheet 1051 may include at least one of a sheet such as a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The diffusion sheet diffuses incident light, and the horizontal and / or vertical prism sheet condenses incident light into a display area. The brightness enhancing sheet improves the brightness by reusing the lost light. A protective sheet may be disposed on the display panel 1061, but the present invention is not limited thereto.

Here, the optical path of the light source module 1031 may include the light guide plate 1041 and the optical sheet 1051 as an optical member, but the invention is not limited thereto.

8 is a view showing a display device having a light emitting device according to an embodiment.

8, the display device 1100 includes a bottom cover 1152, a substrate 1120 on which the above-described light emitting device 1124 is arrayed, an optical member 1154, and a display panel 1155.

The substrate 1120 and the light emitting device 1124 may be defined as a light source module 1160. The bottom cover 1152, the at least one light source module 1160, and the optical member 1154 may be defined as a light unit 1150. The bottom cover 1152 may include a receiving portion 1153, but the present invention is not limited thereto. The light source module 1160 includes a substrate 1120 and a plurality of light emitting devices 1124 arranged on the substrate 1120.

Here, the optical member 1154 may include at least one of a lens, a light guide plate, a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The light guide plate may be made of a PC material or a polymethyl methacrylate (PMMA) material, and the light guide plate may be removed. The diffusion sheet diffuses incident light, and the horizontal and vertical prism sheets condense incident light into a display area. The brightness enhancing sheet enhances brightness by reusing the lost light.

The optical member 1154 is disposed on the light source module 1160 and performs surface light source, diffusion, and light condensation of light emitted from the light source module 1160.

9 is an exploded perspective view of a lighting device having a light emitting device according to an embodiment.

9, the lighting apparatus according to the embodiment includes a cover 2100, a light source module 2200, a heat discharger 2400, a power supply unit 2600, an inner case 2700, and a socket 2800 . Further, the illumination device according to the embodiment may further include at least one of the member 2300 and the holder 2500. The light source module 2200 may include a light emitting device according to an embodiment of the present invention.

For example, the cover 2100 may have a shape of a bulb or a hemisphere, and may be provided in a shape in which the hollow is hollow and a part is opened. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter, or excite light provided from the light source module 2200. The cover 2100 may be a kind of optical member. The cover 2100 may be coupled to the heat discharging body 2400. The cover 2100 may have an engaging portion that engages with the heat discharging body 2400.

The inner surface of the cover 2100 may be coated with a milky white paint. Milky white paints may contain a diffusing agent to diffuse light. The surface roughness of the inner surface of the cover 2100 may be larger than the surface roughness of the outer surface of the cover 2100. This is for sufficiently diffusing and diffusing the light from the light source module 2200 and emitting it to the outside.

The cover 2100 may be made of glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance and strength. The cover 2100 may be transparent so that the light source module 2200 is visible from the outside, and may be opaque. The cover 2100 may be formed by blow molding.

The light source module 2200 may be disposed on one side of the heat discharging body 2400. Accordingly, heat from the light source module 2200 is conducted to the heat discharger 2400. The light source module 2200 may include a light emitting device 2210, a connection plate 2230, and a connector 2250.

The member 2300 is disposed on the upper surface of the heat discharging body 2400 and has guide grooves 2310 into which the plurality of light emitting elements 2210 and the connector 2250 are inserted. The guide groove 2310 corresponds to the substrate of the light emitting device 2210 and the connector 2250.

The surface of the member 2300 may be coated or coated with a light reflecting material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 reflects the light reflected by the inner surface of the cover 2100 toward the cover 2100 in the direction toward the light source module 2200. Therefore, the light efficiency of the illumination device according to the embodiment can be improved.

The member 2300 may be made of an insulating material, for example. The connection plate 2230 of the light source module 2200 may include an electrically conductive material. Therefore, electrical contact can be made between the heat discharging body 2400 and the connecting plate 2230. The member 2300 may be formed of an insulating material to prevent an electrical short circuit between the connection plate 2230 and the heat discharging body 2400. The heat discharger 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to dissipate heat.

The holder 2500 blocks the receiving groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 housed in the insulating portion 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510. The guide protrusion 2510 may have a hole through which the protrusion 2610 of the power supply unit 2600 passes.

The power supply unit 2600 processes or converts an electrical signal provided from the outside and provides the electrical signal to the light source module 2200. The power supply unit 2600 is housed in the receiving groove 2719 of the inner case 2700 and is sealed inside the inner case 2700 by the holder 2500.

The power supply unit 2600 may include a protrusion 2610, a guide unit 2630, a base 2650, and a protrusion 2670.

The guide portion 2630 has a shape protruding outward from one side of the base 2650. The guide portion 2630 may be inserted into the holder 2500. A plurality of components may be disposed on one side of the base 2650. The plurality of components include, for example, a DC converter for converting AC power supplied from an external power source into DC power, a driving chip for controlling driving of the light source module 2200, an ESD (ElectroStatic discharge) protective device, and the like, but the present invention is not limited thereto.

The protrusion 2670 has a shape protruding outward from the other side of the base 2650. The protrusion 2670 is inserted into the connection portion 2750 of the inner case 2700 and receives an external electrical signal. For example, the protrusion 2670 may be equal to or smaller than the width of the connection portion 2750 of the inner case 2700. One end of each of the positive wire and the negative wire is electrically connected to the protrusion 2670 and the other end of the positive wire and the negative wire are electrically connected to the socket 2800.

The inner case 2700 may include a molding part together with the power supply part 2600. The molding part is a hardened portion of the molding liquid so that the power supply unit 2600 can be fixed inside the inner case 2700.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

A first semiconductor layer;
A second semiconductor layer;
An active layer disposed between the first semiconductor layer and the second semiconductor layer; And
And an intermediate layer disposed between the active layer and the second semiconductor layer,
Wherein the intermediate layer comprises:
and an InGaN doped with a p-type dopant,
A first layer adjacent to the active layer and a second layer adjacent to the second semiconductor layer,
Wherein a doping concentration of the dopant of the first layer is lower than a doping concentration of the dopant of the second layer.

The method according to claim 1,
A light emitting element doping concentration of the dopant of the first layer is 1E18 to 1E19 cm ^-3.

The method according to claim 1,
Wherein a doping concentration of the dopant of the second layer is 5E18 to 5E19 cm < ^-3 >.

The method according to claim 1,
Wherein,
A plurality of well layers;
A barrier layer positioned between the well layers and having a bandgap energy greater than the well layer,
Wherein the intermediate layer has a band gap energy larger than a band gap energy of the well layer.

5. The method of claim 4,
Wherein the band gap energy of the first layer is larger than the well layer and smaller than the barrier layer and the second semiconductor layer.

The method according to claim 1,
And an electron blocking layer disposed between the intermediate layer and the second semiconductor layer and having a larger band gap energy than the active layer and the intermediate layer.