KR101915213B1 - Light emitting device - Google Patents

Abstract

A light emitting device according to an embodiment includes a first conductive semiconductor layer; A second conductivity type semiconductor layer; An active layer between the first conductive semiconductor layer and the second conductive semiconductor layer; And an electron blocking layer between the active layer and the second conductive type semiconductor layer, wherein the electron blocking layer includes a first layer and a second layer having a smaller energy band gap than the first layer are alternately laminated at least twice, _Wherein the first layer has a larger energy bandgap than the active layer and the first layer and the second layer are made of In _{x 1} Al _{y 1} GaN _{1 -x 1- y 1} and In _{x 2} Al _{y 2} GaN _{1 -x2- y2} (0 1, 0 = x2 < 1, 0 < y1 < 1, 0 = y2 < 1, x1 < y1, x2 < y2, y1> y2), and the electron blocking layer comprises at least two first layers Or the energy band gaps of at least two second layers are different from each other.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

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 .

Therefore, a transmission module of the optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting, automotive headlights, and traffic lights.

FIG. 1 is a graph showing light output according to wavelength of a general light emitting diode, and FIG. 2 is an energy band diagram of a light emitting diode using an electron blocking layer (EBL) having a superlattice structure to improve light output .

In order for a lighting device using a light emitting diode to completely replace a white light source such as a fluorescent lamp, a high color rendering index, i.e., a high color rendering index (CRI) must be secured in addition to a light efficiency and a long lifetime.

However, referring to FIG. 1 illustrating Blue LED as an example, the light output is high at a short wavelength of 445 to 452 nm, but as seen from the A region, the light output tends to decrease toward a long wavelength. When the light output in the long wavelength region is reduced, it becomes difficult to secure a white light source with high color rendering property.

In order to solve such a problem, a light emitting diode has been used in which an In composition is increased in a well layer of an active layer or an EBL layer having a superlattice structure as shown in FIG. 2 is applied.

However, when the In composition is increased in the well layer of the active layer, the difference in lattice constant between the EBL layer and the EBL layer increases, and the stress applied to the active layer increases. Even if the EBL layer having a superlattice structure is applied, There is a problem that the light output reduction in the long wavelength region is still not solved.

The embodiment intends to improve the light efficiency in the long wavelength region of the light emitting device.

A light emitting device according to an embodiment includes a first conductive semiconductor layer; A second conductivity type semiconductor layer; An active layer between the first conductive semiconductor layer and the second conductive semiconductor layer; And an electron blocking layer between the active layer and the second conductive type semiconductor layer, wherein the electron blocking layer includes a first layer and a second layer having a smaller energy band gap than the first layer are alternately laminated at least twice, Wherein the first layer has a larger energy bandgap than the active layer and the first layer and the second layer are made of In _{x 1} Al _y1 Ga _1-x1-y1 N and In _x2 Al _y2 Ga _1-x2-y2 N Y1 < y2), wherein the electron blocking layer has a composition of at least two first layers having energy band gaps of Or the energy band gaps of at least two second layers are different from each other.

The Al content y2 of the second layer may increase toward the second conductivity type semiconductor layer.

And the Al content y2 of the second layer decreases toward the second conductivity type semiconductor layer.

The first layer may have the same Al content y1.

The Al content y1 of the first layer may increase toward the second conductivity type semiconductor layer.

The Al content y1 of the first layer may decrease toward the second conductivity type semiconductor layer.

The Al content y1 of the first layer may be 0.24 to 0.30, respectively.

The Al content y2 of the second layer may be 0 to 0.18, respectively.

The first layer may have the same energy bandgap.

The energy bandgap of the second layer may increase toward the second conductivity type semiconductor layer.

The energy bandgap of the second layer may decrease as it goes toward the second conductivity type semiconductor layer.

The energy band gap of the first layer may increase toward the second conductivity type semiconductor layer.

The energy bandgap of the first layer may decrease as it goes toward the second conductivity type semiconductor layer.

At least two first layers may have different energy band gaps.

The first layer includes a 1-1 layer nearest to the active layer, a 1-2 layer positioned in the center of the first layer among the plurality of first layers, and a 1-3 layer nearest to the second conductivity type semiconductor layer can do.

The energy band gap of the first layer increases from the first 1-1 layer to the first 1-2 layer, and the energy band gap decreases from the first 1-2 layer to the first 1-3 layer .

The Al content y1 increases from the first layer to the first layer to the first layer, and the Al content y1 decreases from the first layer to the first layer to the first layer, .

The light efficiency of the light emitting device can be improved by improving the light output reduction effect in the long wavelength region.

Further, since the light output is increased in the long wavelength region, a white light source with high efficiency and high color rendering property can be secured.

1 is a graph showing light output according to wavelength of a general light emitting diode,
2 is a diagram showing an energy band diagram of a light emitting diode to which an electron blocking layer (EBL) having a superlattice structure is applied in order to improve light output,
3 and 4 are side cross-sectional views of a light emitting device according to an embodiment,
5 is a diagram showing an energy band diagram of the light emitting device according to the first embodiment,
FIG. 6 is a diagram showing an energy band diagram of a light emitting device according to the second embodiment,
7 is a view showing an energy band diagram of the light emitting device according to the third embodiment,
8 is a diagram showing an energy band diagram of the light emitting device according to the fourth embodiment,
9 is a view showing an energy band diagram of the light emitting device according to the fifth embodiment,
10 is a diagram showing an energy band diagram of the light emitting device according to the sixth embodiment,
11 is a diagram showing an energy band diagram of the light emitting device according to the seventh embodiment,
12 is a diagram showing an energy band diagram of the light emitting device according to the eighth embodiment,
13 is a diagram showing an energy band diagram of the light emitting device according to the ninth embodiment,
FIG. 14 is a graph illustrating optical outputs of light emitting devices according to an embodiment of the conventional light emitting device,
15 is a view illustrating an embodiment of a light emitting device package including the light emitting device according to the embodiments,
16 is a view showing an embodiment of a headlamp in which a light emitting device according to an embodiment is disposed,
17 is a view illustrating a display device in which a light emitting device package according to an embodiment is disposed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

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.

3 and 4 are side cross-sectional views of a light emitting device according to an embodiment. FIG. 3 shows a horizontal light emitting device, and FIG. 4 shows a vertical light emitting device.

The light emitting device according to an exemplary embodiment includes a first conductive semiconductor layer 120, a second conductive semiconductor layer 140, and a second conductive semiconductor layer 140 between the first conductive semiconductor layer 120 and the second conductive semiconductor layer 140 And an electron blocking layer 150 between the active layer 130 and the second conductive semiconductor layer 140.

The light emitting device includes a plurality of compound semiconductor layers, for example, a light emitting diode (LED) using a semiconductor layer of a group III-V element, and the LED is a colored LED emitting light such as blue, green, LED. The emitted light of the LED may be implemented using various semiconductors, but is not limited thereto.

The first conductive semiconductor layer 120, the active layer 130, and the second conductive semiconductor layer 140 may be combined to form a light emitting structure.

The light-emitting structure may be formed by, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD) Molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE), and the like, but the present invention is not limited thereto.

The first conductive semiconductor layer 120 may be formed of a semiconductor compound, for example, a compound semiconductor such as a group III-V element or a group II-VI element. The first conductive type dopant may also be doped. When the first conductive semiconductor layer 120 is an n-type semiconductor layer, the first conductive dopant may include Si, Ge, Sn, Se or Te as an n-type dopant.

The first conductive semiconductor layer 120 includes a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) can do. The first conductive semiconductor layer 120 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP and InP.

The second conductive semiconductor layer 140 may be formed of a semiconductor compound, for example, a group III-V compound semiconductor doped with a second conductive dopant. The second conductivity type semiconductor layer 140 has a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) Semiconductor material. When the second conductive semiconductor layer 140 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, or Ba as a p-type dopant.

In this embodiment, the first conductivity type semiconductor layer 120 may be an n-type semiconductor layer, and the second conductivity type semiconductor layer 140 may be a p-type semiconductor layer.

In addition, an n-type semiconductor layer (not shown) may be formed on the second conductivity type semiconductor layer 140 when the semiconductor having the opposite polarity to the second conductivity type, for example, the second conductivity type semiconductor layer is a p- have. Accordingly, the light emitting structure may have any one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

The active layer 130 is positioned between the first conductive semiconductor layer 120 and the second conductive semiconductor layer 140.

The active layer 130 emits light having energy determined by energy bands inherent in the active layer (light-emitting layer) material when electrons and holes are in contact with each other. For example, when the first conductivity type semiconductor layer 120 is n- Type semiconductor layer and the second conductivity type semiconductor layer 140 is a p-type semiconductor layer, electrons are supplied from the first conductivity type semiconductor layer 120 and holes are injected from the second conductivity type semiconductor layer 140 Can be provided.

The active layer 130 may be formed of at least one of a single well structure, a multi-well structure, a quantum-wire structure, or a quantum dot structure. For example, the active layer 124 may be formed with a multiple quantum well structure by injecting trimethylgallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP / GaN) ) / AlGaP, but the present invention is not limited thereto. The well layer may be formed of a material having a bandgap narrower than the bandgap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 130. The conductive clad layer may be formed of a semiconductor having a band gap wider than the band gap of the barrier layer of the active layer. For example, the conductive clad layer may comprise GaN, AlGaN, InAlGaN or a superlattice structure. Further, the conductive clad layer may be doped with n-type or p-type.

The active layer 130 is formed such that the well layer 132 and the barrier layer 131 are alternately stacked at least once and the energy band gap of the well layer 132 is smaller than the energy band gap of the barrier layer 131.

An electron blocking layer (EBL) 150 may be disposed between the active layer 130 and the second conductive semiconductor layer 140.

Electrons provided in the first conductivity type semiconductor layer 120 do not contribute to light emission and electrons are injected into the second conductivity type semiconductor layer 140 beyond the active layer 130 because electrons in the electron blocking layer 150 have good mobility And can act as a potential barrier to prevent leakage current from flowing out.

The electron blocking layer 150 includes a pair structure in which a first layer 151 and a second layer 152 having a smaller energy bandgap than the first layer 151 are alternately stacked and at least two first layers 151, The energy band gaps of the second layers 151 may be different from each other or the energy band gaps of the at least two second layers 152 may be different from each other.

In FIGS. 3 and 4, the first layer 151 and the second layer 152 are alternately stacked, but the present invention is not limited thereto.

As an example, the pair structure of the first layer 151 and the second layer 152 may be repeated 2 to 6 times.

Since the energy bandgap increases with an increase in the content of Al, the electron blocking layer 150 contains Al and is set to have a larger energy band gap than the active layer 130, so that the electrons provided from the first conductivity type semiconductor layer 120 It is possible to prevent the leakage current from being caused to pass through the active layer 130 and into the second conductivity type semiconductor layer 140 without contributing to light emission.

The first layer 151 and the second layer 152 of the electron blocking layer 150 are formed of In _{x 1} Al _{y 1} Ga _1-x1-y1 N and In _x2 Al _y2 Ga _1-x2-y2 N (0? 1, 0? X2 <1, 0 <y1 <1, 0? Y2 <1, y1> y2).

The first layer 151 and the second layer 152 of the electron blocking layer 150 may each have a thickness of 4 to 10 nm. The second layer 152 may include a second conductive semiconductor layer 140 The energy bandgap can be increased more and more. At this time, the energy bandgap does not increase as the plurality of second layers 152 goes to the second conductivity type semiconductor layer 140, but the energy band gap increases toward the second conductivity type semiconductor layer 140 The energy bandgaps of the at least two second layers 152 may be equal to each other.

Alternatively, the energy bandgap of the second layer 152 may be reduced toward the second conductive semiconductor layer 140. At this time, the energy bandgap does not decrease as the second conductive type semiconductor layer 140 moves toward the second conductive type semiconductor layer 140, but the energy bandgap decreases toward the second conductive type semiconductor layer 140 The energy bandgaps of the at least two second layers 152 may be equal to each other.

In order for the light emitting device to completely replace the conventional white light source, a high color rendering property must be secured. In order to secure a white light source with high color rendering property, the light output should not be reduced even in a long wavelength region.

In order to obtain luminescence in the long wavelength region, the In composition in the well layer 132 of the active layer 130 has to be increased. This increases the lattice constant difference with the electron blocking layer 150, and by the mechanical stress applied to the active layer 130 There is a problem that the recombination rate of electrons and holes decreases.

In the embodiment, the electron blocking layer 150 is formed of a pair structure of the first layer 151 and the second layer 152, and the energy band gap of the first layer 151 and / or the second layer 152 By reducing the mechanical stress between the active layer 130 and the electron blocking layer 150, it is possible to improve the light efficiency reduction phenomenon in the long wavelength region.

The first layer 151 may have the same energy bandgap.

Alternatively, the energy bandgap of the first layer 151 may decrease toward the second conductivity type semiconductor layer 140. In this case, the energy band gap of the plurality of first layers 151 is not reduced as the second conductive semiconductor layer 140 is grown, and the energy band gap is decreased as the second conductive semiconductor layer 140 is grown The energy band gaps of at least two first layers 151 may be equal to each other.

Alternatively, the energy bandgap of the first layer 151 may increase toward the second conductivity type semiconductor layer 140. At this time, the energy band gap of the plurality of first layers 151 is not necessarily increased toward the second conductivity type semiconductor layer 140, but the energy band gap is increased toward the second conductivity type semiconductor layer 140 The energy band gaps of at least two first layers 151 may be equal to each other.

That is, when there are a plurality of the first layers 151, the energy band gaps of the at least two first layers 151 may be different from each other.

Alternatively, the energy band gap of the first layer 151 increases from the active layer 130 toward the second conductive semiconductor layer 140, and then decreases.

That is, the first layer 151 includes a first layer 151-1 closest to the active layer 130, a second layer 151b positioned in the center of the first layer 151, (151-2) and the first to third layers (151-3) closest to the second conductivity type semiconductor layer, and the first to fifth layers (151-1 to 151-2) The energy bandgap increases and the energy bandgap decreases from the first-second layer 151-2 to the first-third layer 151-3.

Since the first layer 151 serves as a barrier to prevent the electrons from the first conductivity type semiconductor layer 120 from flowing into the second conductivity type semiconductor layer 140, May be at least greater than the energy band gap of the second layer 152.

The energy band gap of the electron blocking layer 150 can be controlled by the Al content of the materials constituting the first layer 151 and the second layer 152. [ That is, as the Al content increases, the energy bandgap increases, and as the Al content decreases, the energy bandgap decreases.

The Al content y2 of the second layer 152 may increase as the direction of the second conductivity type semiconductor layer 140 increases. At this time, the Al content y2 does not have to be increased as the second layer 152 of the second conductive type semiconductor layer 140 approaches the second conductivity type semiconductor layer 140, and y2 increases as the layer progresses toward the second conductivity type semiconductor layer 140, The Al content y2 of the second layers 152 may be equal to each other.

Alternatively, the Al content y2 of the second layer 152 may decrease toward the second conductivity type semiconductor layer 140. At this time, the Al content y2 does not have to be decreased as the second layer 152 is further transferred to the second conductive type semiconductor layer 140, but the y2 decreases toward the second conductive type semiconductor layer 140, The Al content y2 of the second layers 152 may be equal to each other.

The first layer 151 may have the same Al content y1.

Alternatively, the Al content y1 of the first layer 151 may increase toward the second conductivity type semiconductor layer 140. At this time, the Al content y1 is not necessarily increased as the plurality of the first layers 151 is moved toward the second conductivity type semiconductor layer 140, and y1 is increased toward the second conductivity type semiconductor layer 140, The Al content y1 of the first layers 151 may be equal to each other.

Alternatively, the Al content y1 of the first layer 151 may decrease toward the second conductivity type semiconductor layer 140. At this time, the Al content y1 does not have to be decreased as the plurality of first layers 151 are moved toward the second conductivity type semiconductor layer 140, and y1 decreases toward the second conductivity type semiconductor layer 140, The Al content y1 of the first layers 151 may be equal to each other.

Alternatively, the Al content y1 of the first layer 151 increases from the first-first layer 151-1 to the first-first layer 151-2, The Al content y1 may decrease as it goes to the first to third layers 151-3.

The Al content y1 of the first layer 151 of the electron blocking layer 150 may be 0.24 to 0.30, but is not limited thereto. If the Al content y1 of the first layer 151 is too large, the difference in lattice constant with the active layer 130 is increased to increase the stress applied to the active layer 130. If the Al content y1 of the first layer 151 is too small It may not function properly as a barrier to block electrons.

The Al content y2 of the second layer 152 of the electron blocking layer 150 may be 0 to 18, but is not limited thereto.

In may be included in the first layer 151 and the second layer 152 of the electron blocking layer 150. In, a small amount of In is included to reduce the lattice constant difference with respect to the active layer 130. For example, the In contents x1 and x2 may be 0 to 0.05, but are not limited thereto. If the In content of the electron blocking layer 150 is too large, the crystallinity of the electron blocking layer 150 may be deteriorated and it may fail to function as a barrier for blocking electrons.

The light emitting structure including the first conductive semiconductor layer 120, the active layer 130, and the second conductive semiconductor layer 140 is grown on the growth substrate 110.

The growth substrate 110 may be formed of a material suitable for semiconductor material growth, a material having excellent thermal conductivity. For example, at least one of sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ O ₃ may be used as the growth substrate 110. The growth substrate 110 may be wet-cleaned to remove impurities on the surface.

The unselected semiconductor layer 115 may be grown before the growth of the first conductivity type semiconductor layer 120 on the growth substrate 110.

The un-doped semiconductor layer 115 is formed to improve the crystallinity of the first conductivity type semiconductor layer 120. The un-doped semiconductor layer 115 may be formed of a material having a lower electrical conductivity than the first conductivity type semiconductor layer 120 And may be the same as the first conductivity type semiconductor layer 120 except that it has conductivity.

The first electrode 160 is disposed on the first conductive semiconductor layer 120 and the second electrode 170 is disposed on the second conductive semiconductor layer 140.

The first electrode 155 and the second electrode 160 may include at least one of aluminum (Al), titanium (Ti), chrome (Cr), nickel (Ni), copper (Cu) Layer structure or a multi-layer structure.

3, the second conductivity type semiconductor layer 140, the active layer 130, and a part of the first conductivity type semiconductor layer 120 are selectively etched to expose the first conductivity type semiconductor layer 140, The first electrode 160 is located on the surface of the first electrode 120.

4, the conductive supporting substrate 210 may be positioned below the second conductive semiconductor layer 140, and the conductive supporting substrate 210 may serve as the second electrode.

The conductive support substrate 210 may be formed of a material having high electrical conductivity and high thermal conductivity. For example, the conductive supporting substrate 210 may be a base substrate having a predetermined thickness and may be made of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), or aluminum (Au), a copper alloy (Cu Alloy), a nickel (Ni), a copper-tungsten (Cu-W), a carrier wafer (e.g., GaN, a Si, Ge, GaAs, ZnO, SiGe, SiC, SiGe, Ga 2 O 3 , etc.) or a conductive sheet or the like may optionally be included.

Referring again to FIG. 3, a transparent electrode layer 180 may be positioned between the second conductive semiconductor layer 140 and the second electrode 170.

The transparent electrode layer 180 is for improving the electrical contact between the second conductive type semiconductor layer 140 and the second electrode 170. The transparent conductive layer and the metal may be selectively used. For example, ITO tin oxide, indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO) ZnO, ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / ZnO, and the like are used as the antimony tin oxide (ATO), gallium zinc oxide (GZO), IZON nitride, At least one of IrOx / Au or Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, Mg, Zn, Pt, Au, And is not limited to such a material.

Referring to FIG. 4, a reflective layer 230 may be disposed between the second conductive semiconductor layer 140 of the light emitting structure and the conductive supporting substrate 210.

The reflective layer 230 may effectively reflect the light generated in the active layer 130 and greatly improve the light extraction efficiency of the light emitting device.

A separate transparent electrode layer 220 may be disposed between the reflective layer 230 and the second conductive semiconductor layer 140.

The transparent electrode layer 220 may not be formed separately and the reflective layer 230 and the second conductive semiconductor layer 140 may be formed on the second conductive semiconductor layer 140. [ Lt; RTI ID = 0.0 &gt; interface. &Lt; / RTI &gt;

The light emitting structure having the reflective layer 230 and / or the transparent electrode layer 220 and the conductive supporting substrate 210 may be coupled to each other by the bonding layer 215.

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, It is not limited thereto.

A roughness pattern may be formed on the surface of the first conductivity type semiconductor layer 120 of the light emitting structure. The roughness pattern can be formed by performing an etching process using a PEC (Photo Enhanced Chemical) etching method or a mask pattern. The roughness pattern is intended to increase the extraction efficiency of light generated in the active layer 130, and may have a regular period or an irregular period.

In addition, the passivation layer 240 may be formed on at least a portion of the side surface of the light emitting structure and the first conductive semiconductor layer 120.

The passivation layer 240 is made of oxide or nitride to protect the light emitting structure. As an example, the passivation layer 240 may comprise a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

Hereinafter, embodiments will be described in more detail with reference to the respective drawings showing an energy band diagram.

5 is a diagram showing an energy band diagram of the light emitting device according to the first embodiment.

The light emitting device according to the first embodiment includes a first conductive semiconductor layer 120, an active layer 130, and a second conductive semiconductor layer 140.

The active layer 130 emits light having energy determined by energy bands inherent in the active layer (light-emitting layer) material when electrons and holes are in contact with each other. For example, when the first conductivity type semiconductor layer 120 is n- Type semiconductor layer and the second conductivity type semiconductor layer 140 is a p-type semiconductor layer, electrons are supplied from the first conductivity type semiconductor layer 120 and holes are injected from the second conductivity type semiconductor layer 140 Can be provided.

The active layer 130 may be formed of at least one of a single well structure, a multi-well structure, a quantum-wire structure, or a quantum dot structure. In FIG. 5, for example, the well layer 132 and the barrier layer 131 are shown to have a multiple quantum well structure in which the layers are alternately stacked three times.

An electron blocking layer 150 is positioned between the active layer 130 and the second conductive semiconductor layer 140.

Electrons provided in the first conductivity type semiconductor layer 120 do not contribute to light emission and electrons are injected into the second conductivity type semiconductor layer 140 beyond the active layer 130 because electrons in the electron blocking layer 150 have good mobility And can act as a potential barrier to prevent leakage current from flowing out.

The electron blocking layer 150 includes a pair structure in which a first layer 151 and a second layer 152 having a smaller energy band gap than the first layer 151 are alternately stacked, (152) may have different energy band gaps.

In FIG. 5, two pairs of the first layer 151 and the second layer 152 are alternately stacked. However, the present invention is not limited thereto.

The first layer 151 and the second layer 152 of the electron blocking layer 150 are formed of In _{x 1} Al _{y 1} Ga _1-x1-y1 N and In _x2 Al _y2 Ga _1-x2-y2 N (0? 1, 0? X2 <1, 0 <y1 <1, 0? Y2 <1, y1> y2).

The first layer 151 serves as a barrier to prevent electrons from flowing into the second conductive type semiconductor layer 140. In the first embodiment, the energy band gaps of the three first layers 151 are all the same .

The energy band gap of the first layer 151 may be controlled by the Al content of the first layer 151. The Al content y1 of the first layer 151 may be 0.24 to 30, Not limited. Since the energy bandgaps of the first layer 151 are all the same, the Al contents y1 of the plurality of first layers 151 may all be the same.

If the Al content y1 of the first layer 151 is too large, the difference in lattice constant with the active layer 130 is increased to increase the stress applied to the active layer 130. If the Al content y1 of the first layer 151 is too small It may not function properly as a barrier to block electrons.

The energy bandgap of the plurality of second layers 152 may be reduced toward the second conductivity type semiconductor layer 140. At this time, the energy bandgap does not decrease as the second conductive type semiconductor layer 140 moves toward the second conductive type semiconductor layer 140, but the energy bandgap decreases toward the second conductive type semiconductor layer 140 The energy bandgaps of the at least two second layers 152 may be equal to each other.

In FIG. 5, the energy band gap of the two second layers 152 is gradually reduced toward the second conductivity type semiconductor layer 140.

The energy band gap of the second layer 152 can be controlled by the Al content of the material constituting the second layer 152 so that the Al content y2 of the second layer 152 is lower than the Al content y2 of the second conductivity type semiconductor layer 140 ) Can be gradually decreased. At this time, the Al content y2 does not have to be decreased as the second layer 152 is further transferred to the second conductive type semiconductor layer 140, but the y2 decreases toward the second conductive type semiconductor layer 140, The Al content y2 of the second layers 152 may be equal to each other.

The Al content y2 of the second layer 152 may be 0 to 0.18, but is not limited thereto. When the energy band gap of the second layer 152 gradually decreases and the Al content y2 of the second layer 152 closest to the second conductivity type semiconductor layer 140 becomes 0, the energy of the second layer 152 The bandgap may be the same as the energy band gap of the barrier layer 132 of the active layer 130. [

5, the Al content y2 of the first second layer 152 adjacent to the active layer 130 may be between 0.12 and 0.18 and the Al content y2 of the second second layer 152 may be between 0.05 and 0.10, But is not limited thereto.

In the case where the In composition in the well layer 132 of the active layer 130 is increased in order to improve the light efficiency in the long wavelength region, the lattice constant difference with the electron blocking layer 150 is increased, The Al content of the second layer 152 of the electron blocking layer 150 is gradually decreased toward the second conductivity type semiconductor layer 140 so that the mechanical stress of the active layer 130 It is possible to improve the light efficiency in the long wavelength region while securing the crystalline quality.

In FIG. 5, the pair structure of the first layer 151 and the second layer 152 is shown as two pairs and two second layers 152 exist. However, The energy band gap of the second layer 152 may gradually decrease toward the second conductivity type semiconductor layer 140.

In the first layer 151 and the second layer 152 of the electron blocking layer 150, In may be included. In, a small amount of In is included to reduce the lattice constant difference with respect to the active layer 130. For example, the In contents x1 and x2 may be 0 to 0.05, but are not limited thereto. If the In content of the electron blocking layer 150 is too large, the crystallinity of the electron blocking layer 150 may be deteriorated and it may fail to function as a barrier for blocking electrons.

6 is a diagram showing an energy band diagram of a light emitting device according to the second embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the second embodiment includes the first conductive semiconductor layer 120, the active layer 130 and the second conductive semiconductor layer 140, and the active layer 130 and the second conductive semiconductor layer 140 The electron blocking layer 150 is formed.

In the first and second embodiments, the energy bandgap decreases as the second layer 152 of the electron blocking layer 150 goes toward the second conductive semiconductor layer 140, The first embodiment differs from the first embodiment in that the energy band gap of the first layer 151 of the electron blocking layer 150 also changes toward the direction of the second conductivity type semiconductor layer 140 in the embodiment. That is, the energy band gaps of the plurality of first layers 151 are not all the same, and the energy band gaps of the at least two first layers 151 may be different from each other.

As in the first embodiment, the energy bandgap of the plurality of second layers 152 may decrease toward the second conductivity type semiconductor layer 140. At this time, the energy bandgap does not decrease as the second conductive type semiconductor layer 140 moves toward the second conductive type semiconductor layer 140, but the energy bandgap decreases toward the second conductive type semiconductor layer 140 The energy bandgaps of the at least two second layers 152 may be equal to each other.

In FIG. 6, the energy band gap of the two second layers 152 is gradually decreased toward the second conductivity type semiconductor layer 140.

Since the energy band gap of the second layer 151 can be controlled by the Al content of the material constituting the second layer 152, the Al content y2 of the second layer 152 is less than the Al content y2 of the second conductive semiconductor layer 140 ) Can be gradually decreased. At this time, the Al content y2 does not have to be decreased as the second layer 152 is further transferred to the second conductive type semiconductor layer 140, but the y2 decreases toward the second conductive type semiconductor layer 140, The Al content y2 of the second layers 152 may be equal to each other.

The energy bandgap of the first layer 151 of the electron blocking layer 150 may decrease toward the second conductive semiconductor layer 140. In this case, the energy band gap of the plurality of first layers 151 is not reduced as the second conductive semiconductor layer 140 is grown, and the energy band gap is decreased as the second conductive semiconductor layer 140 is grown The energy band gaps of at least two first layers 151 may be equal to each other.

In FIG. 6, the energy bandgap of the three first layers 151 is gradually decreased toward the second conductivity type semiconductor layer 140.

Since the energy band gap of the first layer 151 can be controlled by the Al content of the material constituting the first layer 151, the Al content y1 of the first layer 151 is less than the Al content y1 of the second conductive type semiconductor layer 140 ) Can be gradually decreased. At this time, the Al content y1 does not have to be decreased as the plurality of first layers 151 are moved toward the second conductivity type semiconductor layer 140, and y1 decreases toward the second conductivity type semiconductor layer 140, The Al content y1 of the first layers 151 may be equal to each other.

The Al content y1 of the first layer 151 may be 0.24 to 30, but is not limited thereto.

In the embodiment, by gradually changing the Al content of the first layer 151 and the second layer 152 of the electron blocking layer 150 to relax the mechanical stress of the active layer 130, The light efficiency can be improved.

Since the first layer 151 serves as a barrier for blocking electrons provided from the first conductivity type semiconductor layer 120, the energy band gap of the first layer 151 decreases toward the second conductivity type semiconductor layer 140 The energy band gap of the first layer 151 may be greater than the energy band gap of the second layer 152 at least.

7 is a diagram showing an energy band diagram of a light emitting device according to the third embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the third embodiment includes a first conductive semiconductor layer 120, an active layer 130, and a second conductive semiconductor layer 140. The active layer 130 and the second conductive semiconductor layer 140 The electron blocking layer 150 is formed.

In the first embodiment and the third embodiment, the energy bandgaps of the first layer 151 of the electron blocking layer 150 are all the same, but the second layer 152 of the electron blocking layer 150 is the same, And the energy band gap increases toward the second conductivity type semiconductor layer 140, which is different from the first embodiment.

The energy bandgap of the plurality of second layers 152 may increase toward the second conductive semiconductor layer 140. At this time, the energy bandgap does not increase as the plurality of second layers 152 goes to the second conductivity type semiconductor layer 140, but the energy band gap increases toward the second conductivity type semiconductor layer 140 The energy bandgaps of the at least two second layers 152 may be equal to each other.

In FIG. 7, the energy band gap of the two second layers 152 is gradually increased toward the second conductivity type semiconductor layer 140.

The energy band gap of the second layer 152 can be controlled by the Al content of the material constituting the second layer 152 so that the Al content y2 of the second layer 152 is lower than the Al content y2 of the second conductivity type semiconductor layer 140 ) Can be gradually increased. At this time, the Al content y2 does not have to be increased as the second layer 152 of the second conductive type semiconductor layer 140 approaches the second conductivity type semiconductor layer 140, and y2 increases as the layer progresses toward the second conductivity type semiconductor layer 140, The Al content y2 of the second layers 152 may be equal to each other.

The Al content y2 of the second layer 152 may be 0 to 0.18, but is not limited thereto. When the Al content y2 of the second layer 152 closest to the active layer 130 becomes zero when the energy band gap of the second layer 152 gradually increases, the energy band gap of the second layer 152 becomes larger than the energy band gap of the active layer 130. [ May be the same as the energy band gap of the barrier layer 132 of the barrier layer 130.

7, the Al content y2 of the first second layer 152 adjacent to the active layer 130 may be 0.05 to 0.10 and the Al content y2 of the second layer 152 may be 0.12 to 0.18, But is not limited thereto.

In FIG. 7, the pair structure of the first layer 151 and the second layer 152 is shown as two pairs, and two second layers 152 exist. However, The energy band gap of the second layer 152 may gradually increase toward the second conductivity type semiconductor layer 140.

8 is a diagram showing an energy band diagram of a light emitting device according to the fourth embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the fourth embodiment includes a first conductive semiconductor layer 120, an active layer 130, and a second conductive semiconductor layer 140. The active layer 130 and the second conductive semiconductor layer 140 The electron blocking layer 150 is formed.

The energy band gap of the second layer 152 of the electron blocking layer 150 increases in the direction of the second conductivity type semiconductor layer 140 in the third and fourth embodiments, The first layer 151 of the layer 150 also differs from the third embodiment in that the energy band gap increases toward the second conductivity type semiconductor layer 140. [

The energy bandgap of the first layer 151 of the electron blocking layer 150 may increase toward the second conductivity type semiconductor layer 140. At this time, the energy band gap of the plurality of first layers 151 is not necessarily increased toward the second conductivity type semiconductor layer 140, but the energy band gap is increased toward the second conductivity type semiconductor layer 140 The energy band gaps of at least two first layers 151 may be equal to each other.

In FIG. 8, the energy band gap of the three first layers 151 is gradually increased toward the second conductivity type semiconductor layer 140.

Since the energy band gap of the first layer 151 can be controlled by the Al content of the material constituting the first layer 151, the Al content y1 of the first layer 151 is less than the Al content y1 of the second conductive type semiconductor layer 140 ) Can be gradually increased. At this time, the Al content y1 is not necessarily increased as the plurality of the first layers 151 is moved toward the second conductivity type semiconductor layer 140, and y1 is increased toward the second conductivity type semiconductor layer 140, The Al content y1 of the first layers 151 may be equal to each other.

The Al content y1 of the first layer 151 may be 0.24 to 30, but is not limited thereto.

In the embodiment, by gradually changing the Al content of the first layer 151 and the second layer 152 of the electron blocking layer 150 to relax the mechanical stress of the active layer 130, The light efficiency can be improved.

Since the first layer 151 serves as a barrier for blocking electrons provided from the first conductivity type semiconductor layer 120, the energy band gap of the first layer 151 increases as the direction of the second conductivity type semiconductor layer 140 increases The energy band gap of the first layer 151 may be greater than the energy band gap of the second layer 152 at least.

9 is an energy band diagram of the light emitting device according to the fifth embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the fifth embodiment includes a first conductive semiconductor layer 120, an active layer 130, and a second conductive semiconductor layer 140. The active layer 130 and the second conductive semiconductor layer 140 The electron blocking layer 150 is formed.

The electron blocking layer 150 includes a pair structure in which a first layer 151 and a second layer 152 having a smaller energy band gap than the first layer 151 are alternately stacked, (152) may have different energy band gaps.

In FIG. 9, four pairs of the first layer 151 and the second layer 152 are alternately stacked, but the present invention is not limited thereto.

The first layer 151 of the electron blocking layer 150 has the same energy bandgap and the second layer 152 of the electron blocking layer 150 is formed of the second conductive semiconductor layer 140 ) Direction, the energy bandgap can be reduced. At this time, the energy bandgap does not decrease as the second conductive type semiconductor layer 140 moves toward the second conductive type semiconductor layer 140, but the energy bandgap decreases toward the second conductive type semiconductor layer 140 The energy bandgaps of the at least two second layers 152 may be equal to each other.

In FIG. 9, the energy bandgap of the four second layers 152 is gradually decreased toward the second conductivity type semiconductor layer 140.

The energy band gap of the second layer 152 can be controlled by the Al content of the material constituting the second layer 152 so that the Al content y2 of the second layer 152 is lower than the Al content y2 of the second conductivity type semiconductor layer 140 ) Can be gradually decreased. At this time, the Al content y2 does not have to be decreased as the second layer 152 is further transferred to the second conductive type semiconductor layer 140, but the y2 decreases toward the second conductive type semiconductor layer 140, The Al content y2 of the second layers 152 may be equal to each other.

The Al content y2 of the second layer 152 may be 0 to 0.18, but is not limited thereto. When the Al content y2 of the second layer 152 closest to the second conductivity type semiconductor layer 140 becomes zero when the energy band gap of the second layer 152 gradually decreases, The energy band gap of the active layer 130 may be the same as the energy band gap of the barrier layer 132 of the active layer 130.

10 is a diagram showing an energy band diagram of the light emitting device according to the sixth embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the sixth embodiment includes a first conductive semiconductor layer 120, an active layer 130 and a second conductive semiconductor layer 140, and the active layer 130 and the second conductive semiconductor layer 140 The electron blocking layer 150 is formed.

The first layer 151 of the electron blocking layer 150 has the same energy bandgap and the second layer 152 of the electron blocking layer 150 has an energy band as it goes toward the second conductive semiconductor layer 140 The gap may be reduced, but the energy bandgaps of the at least two second layers 152 may be equal to each other.

The energy band gap of the second layer 152 can be controlled by the Al content of the material constituting the second layer 152 so that the Al content y2 of the second layer 152 is lower than the Al content y2 of the second conductivity type semiconductor layer 140 ), But the Al content y2 of at least two second layers 152 may be equal to each other.

In FIG. 10, the energy band gap of the adjacent two second layers 152 is shown as being adjacent to the active layer 130, but the present invention is not limited thereto.

11 is a diagram showing an energy band diagram of the light emitting device according to the seventh embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the seventh embodiment includes a first conductive semiconductor layer 120, an active layer 130, and a second conductive semiconductor layer 140, and the active layer 130 and the second conductive semiconductor layer 140 The electron blocking layer 150 is formed.

The energy band gap of the first layer 151 of the electron blocking layer 150 increases toward the second conductive semiconductor layer 140 and the energy of the energy of the at least two first layers 151 increases The band gaps may be equal to each other.

Since the energy band gap of the first layer 151 can be controlled by the Al content of the material constituting the first layer 151, the Al content y1 of the first layer 151 is less than the Al content y1 of the second conductive type semiconductor layer 140 ), And the Al content y1 of at least two first layers 151 may be equal to each other.

The energy bandgap of the second layer 152 of the electron blocking layer 150 decreases toward the second conductive semiconductor layer 140 while the energy bandgaps of the at least two second layers 152 decrease Can be the same.

The energy band gap of the second layer 152 can be controlled by the Al content of the material constituting the second layer 152 so that the Al content y2 of the second layer 152 is lower than the Al content y2 of the second conductivity type semiconductor layer 140 ), While the Al content y2 of at least two second layers 152 may be equal to each other.

12 is a diagram showing an energy band diagram of a light emitting device according to an eighth embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the eighth embodiment includes a first conductivity type semiconductor layer 120, an active layer 130 and a second conductivity type semiconductor layer 140, and the active layer 130 and the second conductivity type semiconductor layer 140 The electron blocking layer 150 is formed.

In the eighth embodiment, the electron blocking layer 150 includes a pair structure in which a first layer 151 and a second layer 152 having an energy band gap smaller than that of the first layer 151 are alternately stacked, The first layer 151 includes a first 1-1 layer 151-1 closest to the active layer 130, a first 1-2 layer 151-2 located in the center of the plurality of first layers 151, And a first-third layer 151-3 closest to the second conductivity-type semiconductor layer 140.

Although it is shown in FIG. 12 that there are three first layers 151 as an example, it is possible to have a first layer 151 thereon in accordance with the embodiment, and among the plurality of first layers 151, (1-1) layer 151-1 located closest to the first conductive semiconductor layer 130, a first 1-2 layer 151-2 located at the center of the first conductive semiconductor layer 140, And the third layer 151-3 may be located on the first layer.

The energy band gap of the first layer 151 increases from the first 1-1 layer 151-1 to the first 1-2 layer 151-2, The energy bandgap can be reduced toward the 1-3 layer (151-3).

The energy band gap of the first layer 151 is gradually changed from the active layer 130 toward the second conductivity type semiconductor layer 140 so that the mechanical stress between the active layer 130 and the electron blocking layer 150 is relaxed , The light efficiency reduction phenomenon in the long wavelength region can be improved.

In this case, the first layer 151 may have the same energy bandgap, but the present invention is not limited thereto.

Since the energy band gap of the first layer 151 can be controlled by the Al content of the material constituting the first layer 151, the Al content y1 of the first layer 151 is equal to the Al content y1 of the first layer 151- 1 to the first 1-2 layer 151-2 and decreases from the first 1-2 layer 151-2 to the first 1-3 layer 151-3.

13 is a diagram showing an energy band diagram of a light emitting device according to the ninth embodiment. The contents overlapping with the above-described embodiments will not be described again, and the differences will be mainly described below.

The light emitting device according to the ninth embodiment includes a first conductivity type semiconductor layer 120, an active layer 130 and a second conductivity type semiconductor layer 140. The active layer 130 and the second conductivity type semiconductor layer 140 The electron blocking layer 150 is formed.

In the eighth and ninth embodiments, the first layer 151 of the electron blocking layer 150 is divided into a first 1-1 layer 151-1 closest to the active layer 130, a plurality of first layers 151 And a first layer 151-3 closest to the second conductivity type semiconductor layer 140, and the first layer 151 The energy band gap increases from the first 1-1 layer 151-1 to the first 1-2 layer 151-2 and the energy band gap increases from the first 1-2 layer 151-2 toward the 1-3th layer 151 -3), but the energy band gap of the second layer 152 is increased toward the second conductivity type semiconductor layer 140, which is different from the eighth embodiment .

The energy band gap of the second layer 152 can be controlled by the Al content of the material constituting the second layer 152 so that the Al content y2 of the second layer 152 is lower than the Al content y2 of the second conductivity type semiconductor layer 140 ).

Conventionally, when a rapid compositional change is made between the active layer and the electron blocking layer, there is a problem that the quality of the active layer 13 is lowered due to the mechanical stress therebetween and the light efficiency in the long wavelength region is reduced. However, The energy band gap between the layer 151 and the second layer 152 is gradually changed to relax the mechanical stress between the active layer 130 and the electron blocking layer 150 to improve the light efficiency in the long wavelength region have.

FIG. 14 is a graph illustrating optical outputs of light emitting devices according to an embodiment of the conventional light emitting device.

14 shows the result of using Blue LED. In the case of the conventional light emitting device (a), the light output tends to decrease toward the longer wavelength. However, in the case of the light emitting device b according to the embodiment, It does not tend to deteriorate.

That is, according to the embodiment, in the electron blocking layer 150 including the pair structure in which the first layer 151 and the second layer 152 are alternately stacked, the second layer 152, the first layer 151, It can be confirmed that the light efficiency in the long wavelength region is improved while securing crystallinity by moderating the mechanical stress of the active layer 130 by gradually changing the Al content of the second layer 152.

15 is a view illustrating an embodiment of a light emitting device package including the light emitting device according to the embodiments.

The light emitting device package 300 according to an embodiment includes a body 310, a first lead frame 321 and a second lead frame 322 provided on the body 310, A light emitting device 100 according to the above embodiments electrically connected to the first lead frame 321 and the second lead frame 322 and a molding part 340 formed in the cavity. A cavity may be formed in the body 310.

The body 310 may include a silicon material, a synthetic resin material, or a metal material. When the body 310 is made of a conductive material such as a metal material, an insulating layer is coated on the surface of the body 310 to prevent an electrical short between the first and second lead frames 321 and 322 .

The first lead frame 321 and the second lead frame 322 are electrically separated from each other and supply current to the light emitting device 100. The first lead frame 321 and the second lead frame 322 may increase the light efficiency by reflecting the light generated from the light emitting device 100. The heat generated from the light emitting device 100 To the outside.

The light emitting device 100 may be mounted on the body 310 or may be mounted on the first lead frame 321 or the second lead frame 322. The first lead frame 321 and the light emitting element 100 are directly energized and the second lead frame 322 and the light emitting element 100 are connected to each other through the wire 330 in this embodiment. The light emitting device 100 may be connected to the lead frames 321 and 322 by a flip chip method or a die bonding method in addition to the wire bonding method.

The molding part 340 may surround and protect the light emitting device 100. In addition, the phosphor 350 may be included on the molding part 340 to change the wavelength of light emitted from the light emitting device 100.

The phosphor 350 may include a garnet-based phosphor, a silicate-based phosphor, a nitride-based phosphor, or an oxynitride-based phosphor.

For example, the garnet-base phosphor is _{YAG (Y 3 Al 5 O 12} : Ce 3 +) or TAG: may be a _{(Tb 3 Al 5 O 12 Ce} 3 +), wherein the silicate-based phosphor is (Sr, Ba, Mg, Ca) ₂ SiO ₄ : Eu ^{2 +} , and the nitride phosphor may be CaAlSiN ₃ : Eu ^{2 +} containing SiN, and the oxynitride phosphor may be Si _{6 - x Al x O x N 8 -x:} Eu 2 + (0 <x <6) can be.

The light of the first wavelength range emitted from the light emitting device 100 is excited by the fluorescent material 250 to be converted into the light of the second wavelength range and the light of the second wavelength range passes through the lens (not shown) The light path can be changed.

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. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Still another embodiment may be implemented as a display device, an indicating device, a lighting system including the semiconductor light emitting device or the light emitting device package described in the above embodiments, for example, the lighting system may include a lamp, a streetlight .

Hereinafter, the headlamp and the backlight unit will be described as an embodiment of the lighting system in which the above-described light emitting device or the light emitting device package is disposed.

16 is a view showing an embodiment of a headlamp in which a light emitting device according to an embodiment is disposed.

16, the light emitted from the light emitting module 710 in which the light emitting device according to the embodiment is disposed is reflected by the reflector 720 and the shade 730, transmitted through the lens 740, have.

The light emitting module 710 may include a plurality of light emitting devices on a circuit board, but the present invention is not limited thereto.

17 is a view illustrating a display device in which a light emitting device package according to an embodiment is disposed.

17, the display device 800 according to the embodiment includes a light emitting module 830 and 835, a reflection plate 820 on the bottom cover 810, and a reflection plate 820 disposed in front of the reflection plate 820, A first prism sheet 850 and a second prism sheet 860 disposed in front of the light guide plate 840 and a second prism sheet 860 disposed between the first prism sheet 850 and the second prism sheet 860. The light guiding plate 840 guides light emitted from the light- A panel 870 disposed in front of the panel 870 and a color filter 880 disposed in the front of the panel 870.

The light emitting module includes the above-described light emitting device package 835 on the circuit board 830. Here, a PCB or the like may be used for the circuit board 830, and the light emitting device package 835 is as described with reference to FIG.

The bottom cover 810 may house the components in the display device 800. 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 840 or on the front surface of the bottom cover 810 with a highly reflective material Do.

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 840 scatters light emitted from the light emitting device package module so that the light is uniformly distributed 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. The light guide plate 830 may be formed of polymethyl methacrylate (PMMA), polycarbonate (PC), or polyethylene (PE). An air guide system is also available in which the light guide plate is omitted and light is transmitted in a space above the reflective sheet 820.

The first prism sheet 850 is formed on one side of the support film with a transparent and elastic polymeric material, and the polymer may have a prism layer in which a plurality of steric structures are repeatedly formed. As shown in the drawings, the plurality of patterns may be repeatedly provided with a stripe pattern.

In the second prism sheet 860, the edges and the valleys on one surface of the support film may be perpendicular to the edges and the valleys on one surface of the support film in the first prism sheet 850. This is to uniformly distribute the light transmitted from the light emitting module and the reflective sheet in all directions of the panel 870.

In the present embodiment, the first prism sheet 850 and the second prism sheet 860 form an optical sheet, which may be formed of other combinations, for example, a microlens array or a diffusion sheet and a microlens array Or a combination of one prism sheet and a microlens array, or the like.

A liquid crystal display (LCD) panel may be disposed on the panel 870. In addition to the liquid crystal display panel 860, other types of display devices requiring a light source may be provided.

In the panel 870, the liquid crystal is positioned between the glass bodies, and the polarizing plate is placed on both glass bodies to utilize the polarization of light. Here, the liquid crystal has an intermediate property between a liquid and a solid, and liquid crystals, which are organic molecules having fluidity like a liquid, are regularly arranged like crystals. The liquid crystal has a structure in which the molecular arrangement is changed by an external electric field And displays an image.

A liquid crystal display panel used in a display device is an active matrix type, and a transistor is used as a switch for controlling a voltage supplied to each pixel.

A color filter 880 is provided on the front surface of the panel 870 so that light projected from the panel 870 transmits only red, green, and blue light for each pixel.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

110: growth substrate 115: unselected semiconductor layer
120: first conductivity type semiconductor layer 130: active layer
131: barrier layer 132: well layer
150: electron barrier layer 151: first layer
152: second layer 160: first electrode
170: second electrode 180: transparent electrode layer
210: conductive support substrate 215: bonding layer
230: reflective layer 240: passivation layer
310: package body 321, 322: first and second lead frames
330: wire 340: molding part
350: phosphor 710: light emitting module
720: Reflector 730: Shade
800: Display device 810: Bottom cover
820: reflector 840: light guide plate
850: first prism sheet 860: second prism sheet
870: Panel 880: Color filter

Claims (19)

A first conductive semiconductor layer;
A second conductivity type semiconductor layer;
An active layer between the first conductive semiconductor layer and the second conductive semiconductor layer; And
And an electron blocking layer between the active layer and the second conductive semiconductor layer,
Wherein the electron blocking layer has a first layer and a second layer having a smaller energy band gap than the first layer are alternately stacked at least twice, wherein the first layer has a larger energy bandgap than the active layer, Wherein the first layer and the second layer have a larger energy bandgap than the first or second conductivity type semiconductor layer, and the first layer and the second layer have In _{x 1} Al _{y 1} Ga _1-x1-y1 N and In _x2 Al _y2 Ga _1-x2-y2 (0? X1 <1, 0? X2 <1, 0 <y1 <1, 0 <y2 <1, y1> y2)
Wherein the electron blocking layer has different energy band gaps of at least two first layers or different energy band gaps of at least two second layers. The method according to claim 1,
Wherein at least one of the Al content y2 and the energy bandgap increases in the second layer toward the second conductivity type semiconductor layer. The method according to claim 1,
Wherein at least one of the Al content y2 and the energy bandgap decreases in the second layer toward the second conductivity type semiconductor layer. The method according to claim 1,
Wherein the first layer has at least one of an Al content y1 and an energy band gap. The method according to claim 1,
Wherein at least one of the Al content y1 and the energy bandgap increases in the first layer toward the second conductivity type semiconductor layer. The method according to claim 1,
Wherein at least one of the Al content y1 and the energy bandgap decreases in the first layer toward the second conductivity type semiconductor layer. The method according to claim 1,
And the Al content y1 of the first layer is 0.24 to 0.30, respectively. The method according to claim 1,
And the Al content y2 of the second layer is greater than 0 and not greater than 0.18. delete delete delete delete delete delete The method according to claim 1,
The first layer includes a 1-1 layer nearest to the active layer, a 1-2 layer positioned in the center of the first layer among the plurality of first layers, and a 1-3 layer nearest to the second conductivity type semiconductor layer . 16. The method of claim 15,
The first layer has at least one of an Al content y1 and an energy band gap increasing from the first 1-1 layer to the first 1-2 layer, Wherein at least one of the content y1 and the energy band gap is reduced. delete 17. The method of claim 16,
And the energy band gap of the second layer is kept constant. 17. The method of claim 16,
And the energy bandgap increases in the second layer toward the second conductivity type semiconductor layer.

Images