KR101850433B1 - Light emitting device - Google Patents

Abstract

An embodiment includes a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer, and a second semiconductor layer disposed between the first semiconductor layer and the second semiconductor layer and including quantum well layers and quantum barrier layers A barrier layer disposed between the active layer and the second semiconductor layer; and a carrier supplement layer disposed between the active layer and the barrier layer, the carrier supplement layer having the same conductivity as the second semiconductor layer Type dopant is doped, and the concentrations of dopants doped in the carrier supplement layer and the second semiconductor layer are different from each other.

Description

[0001]

Embodiments relate to a light emitting device and a light emitting device package.

BACKGROUND ART Light emitting devices such as a light emitting diode (LD) or a laser diode using semiconductor materials of Group 3-5 or 2-6 group semiconductors are widely used for various colors such as red, green, blue, and ultraviolet And it is possible to realize white light rays with high efficiency by using fluorescent materials or colors, and it is possible to realize low energy consumption, semi-permanent life time, quick response speed, safety and environment friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps .

In general, an epitaxial structure used in a light emitting diode is composed of an electron injection layer, an active layer, and a hole injection layer. The active layer may be a multi-quantum well structure, and may generally be composed of hetero-junctions of undoped Group III-V semiconductors.

The light intensity or the operating voltage of the light emitting diode can be determined by the injection efficiency and recombination rate of electrons and holes transferred from the electron injection layer and the hole injection layer to the active layer.

An electron blocking layer (EBL) may be formed between the active layer and the hole injection layer in order to improve injection efficiency and recombination rate of electrons and holes. For the structure of the above-described light emitting diode, the electron injection layer, the active layer, the electron blocking layer, and the hole injection layer, please refer to Publication No. 2008-0010136.

The embodiment provides a light emitting device capable of improving the brightness and reducing the operating voltage.

The light emitting device according to the embodiment includes a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer, and a second semiconductor layer disposed between the first semiconductor layer and the second semiconductor layer, wherein the quantum well layers and the quantum barrier layer A barrier layer disposed between the active layer and the second semiconductor layer, and a carrier supplement layer disposed between the active layer and the barrier layer, wherein the carrier supplement layer is the same as the second semiconductor layer The conductivity type dopant is doped, and the concentration of the dopant doped in each of the carrier supplement layer and the second semiconductor layer is different from each other.

The concentration of the first dopant doped in the carrier supplement layer may be smaller than the concentration of the second dopant doped in the second semiconductor layer.

The thickness of the carrier supplement layer may be 3 nm to 15 nm.

The dopant doped in each of the carrier supplement layer and the second semiconductor layer may be a P-type dopant.

The concentration of the first dopant may be 1/20 to 1/2 times the concentration of the second dopant. The concentration of the first dopant is ^{1 * 10 19 cm -3 ~ 2} * 10 19 cm - ³ and the concentration of the second dopant may be a ^{1 * 10 20 cm -3 ~ 2} * 10 20 cm -3.

Wherein the carrier supplement layer and the second conductivity type semiconductor layer have a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? Mg, Zn, Ca, Sr, or Ba may be doped.

The light emitting device includes a substrate disposed below the first semiconductor layer, a conductive layer disposed on the second semiconductor layer, a first electrode in ohmic contact with the first conductive semiconductor layer, And a second electrode disposed on the conductive layer.

The light emitting device may further include an ohmic layer disposed under the second semiconductor layer, a reflective layer disposed under the ohmic layer, a passivation layer disposed on a side surface of the light emitting structure, and a first electrode disposed on the first semiconductor layer, .

Embodiments can improve the brightness and reduce the operating voltage.

1 is a cross-sectional view of a light emitting device according to an embodiment.
Fig. 2 shows an energy band diagram of the light emitting structure shown in Fig.
Fig. 3 shows the operating voltage of the light emitting device shown in Fig.
FIG. 4 shows an energy band diagram of a multiple quantum well structure of a general light emitting device upon current application.
Fig. 5 shows an energy band diagram of a multiple quantum well structure of the light emitting device shown in Fig. 1 when current is applied.
6 shows a light emitting device according to another embodiment.
7 shows a light emitting device package according to an embodiment.
8 is an exploded perspective view of a lighting device including a light emitting device package according to an embodiment.
9A shows a display device including a light emitting device package according to an embodiment.
Fig. 9B is a sectional view of the light source portion of the display device shown in Fig. 9A.

Hereinafter, embodiments will be described with reference to the accompanying drawings.

In the description of the embodiments, it is to be understood that each layer (film), region, pattern or structure is formed "on" or "under" a substrate, each layer The terms " on "and " under " encompass both being formed" directly "or" indirectly " In addition, the criteria for above or below each layer will be described with reference to the drawings.

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 of each component does not entirely reflect the actual size. Hereinafter, a light emitting device according to an embodiment will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a light emitting device 100 according to an embodiment, and FIG. 2 is an energy band diagram of the light emitting structure 120 shown in FIG.

1 and 2, a light emitting device 100 includes a substrate 110, a first conductive semiconductor layer 122, an active layer 124, a carrier supplement layer 125, an electron blocking layer A conductive layer 130, a first electrode 142 and a second electrode 144. The light emitting structure 120 includes a first conductive semiconductor layer 128, a second conductive semiconductor layer 128, and a second conductive semiconductor layer 128.

The substrate 110 supports the light emitting structure 120. The substrate 110 may be any one of a sapphire substrate, a silicon substrate, a zinc oxide (ZnO) substrate, a nitride semiconductor substrate, or a template substrate in which at least one of GaN, InGaN, AlGaN, and AlInGaN is stacked. have.

The light emitting structure 120 is disposed on the substrate 110, and generates light.

The light emitting structure 120 includes a first conductive semiconductor layer 122, an active layer 124, a carrier supplement layer 125, an electron blocking layer 126, and a second conductive semiconductor layer 128, (110). ≪ / RTI > The light emitting structure 120 may expose a part of the first conductivity type semiconductor layer 122.

For example, the second conductivity type semiconductor layer 126, the active layer 124, the carrier supplement layer 125, the electron blocking layer 126, and the first conductive type semiconductor layer 122 are formed to expose a part of the first conductivity type semiconductor layer 122, A part of the semiconductor layer 122 can be etched.

A buffer layer (not shown) may be interposed between the substrate 110 and the light emitting structure 120 to mitigate the difference between the lattice constant and the thermal expansion coefficient, and the crystallinity of the first conductivity type semiconductor layer 122 may be improved An undoped semiconductor layer (not shown) may be interposed.

At this time, the buffer layer may be grown at a low temperature, and the material may be a GaN layer or an AlN layer, but the present invention is not limited thereto. The n-type dopant is not doped, And may be the same as the first conductivity type semiconductor layer 122 except for having electrical conductivity.

The conductive layer 130 not only reduces the total reflection but also increases light extraction efficiency of the light emitted from the active layer 124 to the second conductivity type semiconductor layer 126 because of its good translucency.

The conductive layer 130 may be formed of a transparent conductive oxide such as indium tin oxide (ITO), tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), indium aluminum zinc oxide Indium Gallium Zinc Oxide), IGTO (Indium Gallium Tin Oxide), AZO (Aluminum Zinc Oxide), ATO (Antimony Tin Oxide), GZO (Gallium Zinc Oxide), IrOx, RuOx, RuOx / ITO, Ni, / Au, or Ni / IrOx / Au / ITO.

The first electrode 142 is disposed on the exposed first conductive semiconductor layer 122 and is in ohmic contact with the first conductive semiconductor layer 122. The second electrode 144 is disposed on the conductive layer 130.

Hereinafter, the light emitting structure 120 will be described in detail.

The first conductive semiconductor layer 122 is disposed on the substrate 110 and may be a nitride semiconductor layer. For example, the first conductivity type semiconductor layer 122 may be a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + (For example, an n-type dopant such as Si, Ge, Sn, Se, or Te) may be any one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN and AlInN Lt; / RTI > In FIG. 2, the first conductivity type semiconductor layer 122 is represented by an electron injection layer, and the second conductivity type semiconductor layer 128 is represented by a hole injection layer. The thickness of the first conductivity type semiconductor layer 122 may be 6 nm to 8 nm.

The second conductive semiconductor layer 126 is disposed on the first conductive semiconductor layer 122 and may be a nitride semiconductor layer. The second conductive semiconductor layer 126 may be a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? (For example, a p-type dopant such as Mg, Zn, Ca, Sr, or Ba) may be doped in the second conductive type dopant, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, have. The thickness of the second conductivity type semiconductor layer 126 may be 40 nm to 80 nm.

The active layer 124 is disposed between the first conductivity type semiconductor layer 122 and the second conductivity type semiconductor layer 128. The active layer 124 can generate light by energy generated in the recombination process of the electron provided from the electron injection layer 122 and the hole provided from the hole injection layer 128 .

The active layer 124 may include any one of a single quantum well structure, a multiple quantum well structure, a quantum dot structure, and a quantum wire structure. In the case where the active layer 124 is a quantum well structure, the active layer 124 may be formed of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + And a barrier layer having a composition formula of In _a Al _b Ga _{1 -a b} N (0? A? 1, 0? _B ? 1, 0? A + b? 1) Lt; / RTI >

2, the active layer 124 may include a plurality of quantum well layers (QW1 to QWn, a natural number of n> 1) and quantum barrier layers (QB1 to QBm, m> 1). At this time, the quantum well layer and the quantum barrier layer may alternately be repeated at least once between the first conductive type semiconductor layer and the carrier supplement layer 125. The energy bandgap of the quantum barrier layers QB1 to QBm, e.g., m = 3 is larger than the energy bandgap of the quantum well layers QW1 to QWn, e.g., n = 3. At this time, the quantum barrier layers QB1 to QBm, e.g., m = 3, and the quantum well layers QW1 to QWn, e.g., n = 3 may be undoped undoped layers.

The thickness of each of the quantum barrier layers QB1 to QBm such as m = 2 may be between 5 nm and 7 nm and the thickness of each of the quantum well layers QW1 to QWn, e.g., n = 3 may be between 2 nm and 4 nm. have. For example, the thickness of each of the quantum barrier layers (QB1 to QBm, e.g., m = 2) is 6 nm, and the thickness of each of the quantum well layers (QW1 to QWn, e.g., n = 3) may be 3 nm.

At this time, in order to prevent the p-type dopant (for example, Mg) from diffusing from the hole injection layer 128 into the active layer 124, the last quantum barrier layer QW3 of the quantum barrier layers QW1 to QWn, May be equal to or greater than the thickness of the remaining quantum barrier layers (QB1 to QBm, e.g., m = 2) of the active layer 124. [ The final quantum barrier layer QW3 serves as a diffusion preventing layer for preventing the p-type dopant from penetrating the active layer 124 from the hole injection layer 128. [

A carrier supplement layer 125 is disposed between the active layer 124 and the electron blocking layer 126 and serves to replenish carriers (e.g., holes) in the active layer 124.

The carrier supplement layer 125 may be a nitride semiconductor layer. The carrier supplement layer 125 may be formed of 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? 1) , AlGaN, InGaN, InN, InAlGaN, AlInN and the like, and a second conductive dopant (for example, a p-type dopant such as Mg, Zn, Ca, Sr or Ba) may be doped.

The thickness of the carrier supplement layer 125 may be 1 nm to 15 nm. For example, the thickness of the carrier supplement layer 125 may be 3 nm to 5 nm.

The concentration (hereinafter referred to as "first concentration") of the second conductivity type dopant doped in the carrier supplement layer 125 is determined by the concentration of the second conductivity type dopant doped in the second conductivity type semiconductor layer 128 2 concentration ").

The first concentration may be less than the second concentration. The first concentration may be 1/20 times to 1/2 times the second concentration. For example, the first concentration of Mg doped in the carrier supplement layer 125 may be 1 * 10 ¹⁹ cm ^-3 to 2 * 10 ¹⁹ cm ^-3 , and the concentration of Mg doped in the second conductivity type semiconductor layer 128 The second concentration may be 1 * 10 ²⁰ cm ^-3 to 2 * 10 ²⁰ cm ^-3 . Where * is a multiplication operator.

The energy band gap of the carrier supplement layer 125 may be equal to the energy band gap of the quantum barrier layers QW1 to QWn, e.g., n = 3.

The blocking layer 126 is disposed between the carrier supplement layer 125 and the second conductivity type semiconductor layer 128. The carrier injected from the first conductivity type semiconductor layer 122 into the active layer 124 is a second conductivity type The light emitting efficiency can be improved by blocking the movement to the semiconductor layer 128.

For example, the barrier layer 126 may be an electron blocking layer, as shown in FIG. Hereinafter, the electron blocking layer will be described as an electron blocking layer, but the embodiment is not limited thereto.

The electron blocking layer 126 is disposed between the carrier replenishment layer 125 and the hole injection layer 128 and electrons injected from the electron injection layer 122 into the active layer 124 move to the hole injection layer 128 The light emitting efficiency can be improved.

The electron blocking layer 126 may be a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, the electron blocking layer 126 may be any one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, and AlInN.

The energy band gap of the electron blocking layer 126 may be greater than the energy band gap of the quantum barrier layers QW1 to QWn of the active layer 124 (e.g., n = 3) and the energy band gap of the carrier supplement layer 125 . The energy band gap of the electron blocking layer 126 is larger than the energy band gap of the hole injection layer 128. The thickness of the electron blocking layer 126 may be between 10 nm and 60 nm.

The thickness of the carrier supplement layer 125 may be smaller than the thickness of the final barrier layer QW3 of the active layer 124 and the thickness of the final barrier layer QW3 may be smaller than the thickness of the electron blocking layer 126. [ Or the thickness of the carrier supplement layer 125 may be smaller than the thickness of the electron blocking layer 126. The thickness of the carrier supplement layer 125 may be smaller than the thickness of the carrier supplement layer 125,

In general, the luminous intensity or the operating voltage of the light emitting device can be determined by the injection efficiency and the light emitting recombination ratio of electrons and holes injected from the electron injection layer and the hole injection layer into the active layer. A second conductive semiconductor layer (for example, a hole injection layer) doped with a dopant (for example, a p-type dopant) is grown after growing the active layer having a multiple quantum well structure, and a dopant doped in the second conductive semiconductor layer is grown as an active layer The last barrier layer of the active layer may be grown thicker than the other barrier layers of the active layer to prevent diffusion. However, when the last barrier layer of the active layer is thickened to protect the active layer, the distance between the hole injection layer and the active layer increases, so that the injection efficiency of holes from the hole injection layer to the active layer decreases, It is possible to cause an increase in the operating voltage.

However, the embodiment is provided with a carrier supplement layer 125 disposed between the last barrier layer QB3 of the active layer 124 and the electron blocking layer 126 and further supplementing the carrier (e.g., holes) with the active layer 124 The luminous intensity of the light emitting element 100 can be improved and the operating voltage can be reduced.

Fig. 3 shows the operating voltage of the light emitting device shown in Fig. 3 shows an operating voltage of the light emitting device 100 for obtaining a constant bias current (e.g., 20 mA) and an operating voltage of a general light emitting device.

 f1 represents an operating voltage of the light emitting device 100 according to the embodiment shown in Fig. 1, and f2 represents a general operating voltage of the light emitting device. The x-axis represents the operating voltage and the unit is Volts. The y-axis represents the frequency, i.e., the number of light emitting elements.

Referring to FIG. 3, it can be seen that the operating voltage of the light emitting device 100 according to the embodiment decreases when compared with the operating voltage of a general light emitting device.

FIG. 4 shows an energy band diagram of a multiple quantum well structure of a light emitting device when a current is applied, and FIG. 5 shows an energy band diagram of a multiple quantum well structure of the light emitting device 100 shown in FIG.

Generally, the electron blocking layer functions to prevent the carrier of the active layer from overflowing into the hole injection layer, but conversely, the hole of the hole injection layer may be prevented from moving to the active layer.

The solid line circle 501 shown in FIG. 5 represents the last barrier layer QW3 of the active layer 124, the solid line circle 501 shown in FIG. A carrier supplement layer 125, and an electron blocking layer 126 region.

Referring to FIGS. 4 and 5, in the embodiment, when the bias is applied, the interference of the electron blocking layer 126 from the hole injection layer to the active layer 124 ) May increase the hole transport.

In addition, since the effect of reducing the thickness of the electron blocking layer 126 is shown when the bias is applied, the holes can tunnel the electron blocking layer 126 to move the holes from the hole injection layer to the active layer 124 .

That is, in the embodiment, the movement of holes from the hole injection layer to the active layer 124 is increased to improve the brightness and reduce the operating voltage.

In addition, since the embodiment supplies holes separately to the active layer 124 by the carrier supplement layer 125, it is possible to improve the luminous efficiency and brightness, and reduce the operating voltage.

6 shows a light emitting device 200 according to another embodiment. 6, the light emitting device 200 includes a second electrode layer 205, a passivation layer 230, a second conductive semiconductor layer 128, an electron blocking layer 126, a carrier supplement layer 125, An active layer 124 and a first conductive semiconductor layer 122, a passivation layer 250, and a first electrode 255. The same reference numerals as those in FIG. 1 denote the same components, and duplicate contents of the foregoing description will be omitted or briefly explained.

The second electrode layer 205 includes a support substrate 210, a bonding layer 215, a reflective layer 220, and an ohmic layer 225. The support substrate 210 supports the light emitting structure 240 and provides power to the light emitting structure 240 together with the first electrode 255.

The support substrate 210 may be formed of a conductive material and may be formed of a metal such as copper (Cu), gold (Au), nickel (Ni), molybdenum (Mo), or copper-tungsten Material or a semiconductor including at least one of Si, Ge, GaAs, ZnO, and SiC.

The bonding layer 215 is disposed on the supporting substrate 210. The bonding layer 215 is formed as a bonding layer below the reflective layer 220. The bonding layer 215 is in contact with the reflective layer 220 and the ohmic layer 225 so that the reflective layer 220 and the ohmic layer 225 can be bonded to the supporting substrate 210. The bonding layer 215 includes a barrier metal or a bonding metal and may include at least one of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag or Ta.

The reflective layer 220 is disposed on the bonding layer 215. The reflective layer 220 reflects light incident from the light emitting structure 240, thereby improving light extraction efficiency. The reflective layer 220 may be formed of a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf. The reflective layer 220 may be formed of a multilayer structure including a metal (or an alloy) and a light-transmitting conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO. For example, the reflective layer 220 may be formed of IZO / Ni, AZO / Ag, IZO / Ag / Ni, or AZO / Ag / Ni.

The ohmic layer 225 is disposed on the reflective layer 220. The ohmic layer 225 may be in ohmic contact with the second conductive semiconductor layer 128 of the light emitting structure 240 to supply power to the light emitting structure 240 smoothly. The ohmic layer 225 may selectively use a transparent conductive layer and a metal. The ohmic layer 225 may be made of a metal such as ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrO _x , RuO _x , RuO _x / Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO.

The ohmic layer 225 may be omitted and a material used as the reflective layer 220 may be selected as a material that makes an ohmic contact with the second conductive semiconductor layer 242 so that the reflective layer 220 may be a second conductive type The ohmic contact with the semiconductor layer 128 can be achieved.

The protective layer 230 is disposed on the edge region of the second electrode layer 205. The protective layer 230 can reduce the phenomenon that the interface between the light emitting structure 240 and the bonding layer 215 is peeled off and the reliability of the light emitting device 200 is deteriorated.

The protective layer 230 may be disposed on the edge region of the bonding layer 215. When the bonding layer 215 is not formed, the protective layer 230 may be disposed on the edge region of the supporting substrate 210.

The protective layer 230 may be a conductive material or a nonconductive material. For example, the conductive protective layer may be formed of a transparent conductive oxide film or may include at least one of a metal material such as Ti, Ni, Pt, Pd, Rh, Ir,

For example, the nonconductive protective layer may be formed of a material having a lower electrical conductivity than the reflective layer 220 or the ohmic layer 225, a material forming a Schottky contact with the second conductive semiconductor layer 242, or an electrically insulating material . For example, non-conductive protective layer may be formed of ZnO or SiO _2.

The light emitting structure 240 is disposed on the second electrode layer 205. The light emitting structure 240 includes a second conductive semiconductor layer 128, an electron blocking layer 126, a carrier supplement layer 125, an active layer 124, and a first conductive semiconductor layer 128, (122) may be sequentially stacked.

The carrier supplement layer 125 is disposed between the active layer 124 and the electron blocking layer 126 and serves to supply a carrier (e.g., a hole) to the active layer separately from the second conductivity type semiconductor layer 128. The carrier supplement layer 125 also reduces the interference of the electron blocking layer 126 with respect to the holes in the valence band when the bias is applied and allows the holes to tunnel the electron blocking layer 126, The movement of holes from the conductive semiconductor layer 128 to the active layer 124 can be increased.

The passivation layer 250 may be formed on the side of the light emitting structure 240 to electrically protect the light emitting structure 240, but the present invention is not limited thereto. For example, the passivation layer 250 is _{SiO 2, SiO x, SiO x} N y, Si ₃ N ₄ , Al ₂ O ₃ .

A roughness 260 may be formed on the upper surface of the first conductive semiconductor layer 122 to increase light extraction efficiency. The first electrode 255 is disposed on the first conductivity type semiconductor layer 122. The roughness 260 may be formed on the portion of the first conductive semiconductor layer 122 under the first electrode 255 or not.

7 shows a light emitting device package according to an embodiment. 7, the light emitting device package includes a package body 710, a first metal layer 712, a second metal layer 714, a light emitting element 720, a reflector 725, a wire 730, 740).

The package body 710 has a cavity in which a cavity is formed. At this time, the side wall of the cavity may be formed to be inclined. The package body 710 may be formed of a substrate having good insulating or thermal conductivity such as a silicon based wafer level package, a silicon substrate, silicon carbide (SiC), aluminum nitride (AlN) Or may be a structure in which a plurality of substrates are stacked. The embodiments are not limited to the material, structure, and shape of the body described above.

The first metal layer 712 and the second metal layer 714 are disposed on the surface of the package body 710 such that the first metal layer 712 and the second metal layer 714 are electrically separated from each other in consideration of heat discharge or mounting of the light emitting device. The light emitting device 720 is electrically connected to the first metal layer 712 and the second metal layer 714. Here, the light emitting device 720 may be the light emitting device 100 or 200 shown in FIG. 1 or FIG.

For example, the second electrode layer 205 of the light emitting device 200 is electrically connected to the second metal layer 714, and the first electrode 255 is electrically connected to the first metal layer 712 by the wire 730 .

6, the first electrode 142 of the light emitting device 100 is electrically connected to the first metal layer 712 by wires (not shown), and the second electrode 144 is electrically connected to the first metal layer 712 And may be electrically connected to the second metal layer 714.

The reflection plate 725 is formed on the cavity side wall of the package body 710 so as to direct the light emitted from the light emitting element 720 in a predetermined direction. The reflective plate 725 is made of a light reflecting material, and may be, for example, a metal coating or a metal flake.

The encapsulation layer 740 surrounds the light emitting element 720 located in the cavity of the package body 710 to protect the light emitting element 720 from the external environment. The sealing layer 740 is made of a colorless transparent polymer resin material such as epoxy or silicone. The sealing layer 740 may include a phosphor to change the wavelength of light emitted from the light emitting device 720. The light emitting device package can mount at least one of the feet and the elements according to the above-described embodiments, but is not limited thereto.

A plurality of light emitting device packages according to embodiments may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, and the like may be disposed on the light path of the light emitting device package. The light emitting device package, the substrate, and the optical member may function as a backlight unit.

Still another embodiment may be implemented as a display device, an indicating device, and a lighting system including the light emitting device or the light emitting device package described in the above embodiments. For example, the lighting system may include a lamp and a streetlight.

8 is an exploded perspective view of a lighting device including a light emitting device package according to an embodiment. 8, the illumination device according to the embodiment includes a light source 750 for projecting light, a housing 700 having a light source 7500, a heat dissipation unit 740 for emitting heat of the light source 750, And a holder 760 coupling the heat sink 750 and the heat dissipating unit 740 to the housing 700.

The housing 700 includes a socket coupling portion 710 coupled to an electric socket (not shown), and a body portion 730 connected to the socket coupling portion 710 and having a light source 750 embedded therein. One air flow hole 720 may be formed through the body portion 730.

A plurality of air flow holes 720 are provided on the body portion 730 of the housing 700 and one or more air flow holes 720 may be provided. The air flow port 720 may be disposed radially or in various forms on the body portion 730.

The light source 750 includes a plurality of light emitting device packages 752 provided on the substrate 754. [ The substrate 754 may have a shape that can be inserted into the opening of the housing 700 and may be made of a material having a high thermal conductivity to transmit heat to the heat dissipating unit 740 as described later. The plurality of light emitting device packages may be the embodiment shown in Fig.

A holder 760 is provided below the light source 750, and the holder 760 may include a frame and other air flow holes. Although not shown, an optical member may be provided under the light source 750 to diffuse, scatter, or converge light projected from the light emitting device package 752 of the light source 750.

FIG. 9A shows a display device including the light emitting device package according to the embodiment, and FIG. 9B is a sectional view of the light source part of the display device shown in FIG. 9A.

9A and 9B, the display device includes a backlight unit and a liquid crystal display panel 860, a top cover 870, and a fixing member 850.

The backlight unit includes a bottom cover 810, a light emitting module 880 provided on one side of the bottom cover 810, a reflection plate 820 disposed on the front surface of the bottom cover 810, A light guide plate 830 disposed in front of the light guide plate 820 and guiding light emitted from the light emitting module 880 toward the front of the display device and an optical member 840 disposed in front of the light guide plate 30. The liquid crystal display device 860 is disposed in front of the optical member 840. The top cover 870 is provided in front of the liquid crystal display panel 860 and the fixing member 850 is disposed in the bottom cover 810, (870) to fix the bottom cover 810 and the top cover 870 together.

The light guide plate 830 guides the light emitted from the light emitting module 880 to be emitted in the form of a surface light source and the reflection plate 820 disposed behind the light guide plate 830 reflects light emitted from the light emitting module 880 Is reflected in the direction of the light guide plate 830, thereby enhancing light efficiency. However, the reflection plate 820 may be formed as a separate component as shown in the drawing, or may be formed to be coated on the rear surface of the light guide plate 830 or on the front surface of the bottom cover 810 with a highly reflective material . Here, the reflection plate 820 can be made of a material having a high reflectance and can be used in an ultra-thin shape, and polyethylene terephthalate (PET) can be used.

The light guide plate 830 scatters the light emitted from the light emitting module 880 and uniformly distributes the light over the entire screen area of the LCD. Accordingly, the light guide plate 830 is made of a material having a good refractive index and transmittance, and may be formed of polymethyl methacrylate (PMMA), polycarbonate (PC), or polyethylene (PE).

An optical member 840 is provided at an upper portion of the light guide plate 830 to diffuse the light emitted from the light guide plate 830 at a predetermined angle. The optical member 840 allows the light guided by the light guide plate 830 to be uniformly irradiated toward the liquid crystal display panel 860. As the optical member 840, an optical sheet such as a diffusion sheet, a prism sheet, or a protective sheet may be selectively laminated, or a microlens array may be used. At this time, a plurality of optical sheets may be used, and the optical sheet may be made of a transparent resin such as an acrylic resin, a polyurethane resin, or a silicone resin. It is to be noted that the fluorescent sheet may be included in the prism sheet described above.

A liquid crystal display panel 860 may be provided on the front surface of the optical member 840. Here, it goes without saying that other types of display devices requiring a light source besides the liquid crystal display panel 860 may be provided. A reflection plate 820 is placed on the bottom cover 810 and a light guide plate 830 is placed on the reflection plate 820. Thus, the reflection plate 820 may be in direct contact with the heat radiation member (not shown). The light emitting module 880 includes a light emitting device package 882 and a printed circuit board 881. The light emitting device package 882 is mounted on the printed circuit board 881. Here, the light emitting device package 881 may be the embodiment shown in FIG.

The printed circuit board 881 may be bonded onto the bracket 812. Here, the bracket 812 is made of a material having a high thermal conductivity for dissipating heat in addition to fixing the light emitting device package 882. Although not shown, a heat pad is provided between the bracket 812 and the light emitting device package 882 Thereby facilitating heat transfer. The horizontal portion 812a is supported by the bottom cover 810 and the vertical portion 812b is fixed to the printed circuit board 881 can do.

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.

110, 210: substrate 120, 240:
122: first conductivity type semiconductor layer 124: active layer
125: Carrier replacement layer 126: Electron barrier layer
128: second conductivity type semiconductor layer 130: conductive layer
142, 255: first electrode 144: second electrode
205: second electrode layer 220: reflective layer
225: Ohmic layer 230: Protective layer
240: passivation layer 260: roughness
QW1 to QW3: quantum well layers QB1 to QB3: quantum barrier layers.

Claims (9)

A first semiconductor layer;
A second semiconductor layer disposed on the first semiconductor layer;
An active layer disposed between the first semiconductor layer and the second semiconductor layer, the active layer including quantum well layers and quantum barrier layers;
An electron blocking layer disposed between the active layer and the second semiconductor layer; And
And a carrier supplement layer disposed between the last quantum barrier layer and the electron blocking layer of the active layer among the quantum barrier layers,
Wherein the carrier supplement layer is doped with a dopant of the same conductivity type as that of the second semiconductor layer,
Wherein the concentration of the conductive type dopant in the carrier supplement layer is 1/20 times to 1/2 times the concentration of the conductive type dopant in the second semiconductor layer. The method according to claim 1,
Wherein the last quantum barrier layer is thickest among the quantum barrier layers. The method according to claim 1,
Wherein the carrier supplement layer has a thickness of 3 nm to 5 nm. The method according to claim 1,
Wherein the carrier supplement layer and the second semiconductor layer have a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) And the dopant doped in each of the second semiconductor layers is a P-type dopant. 3. The method of claim 2,
Wherein the thickness of the carrier supplement layer is smaller than the thickness of the last quantum barrier layer,
Wherein the thickness of the last quantum barrier layer is smaller than the thickness of the electron blocking layer. The method according to claim 1,
The concentration of the dopant doped in the carrier supplement layer is 1 x 10 ¹⁹ cm ^-3 to 2 x 10 ¹⁹ cm ^-3 ,
Wherein a concentration of a dopant doped in the second semiconductor layer is 1 x 10 ²⁰ cm ^-3 to 2 x 10 ²⁰ cm ^-3 . delete delete delete

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