KR20110139592A - Light emitting element - Google Patents

Abstract

PURPOSE: A light emitting device is provided to reduce the operation voltage of a light emitting device by increasing the diffusion length of a hole into an active layer. CONSTITUTION: In a light emitting device, an active layer(240) locates between an n-type nitride semiconductor layer and a p-type nitride semiconductor layer(250). The active layer generates light through recombination of an electronic and a hole. The active layer has a plurality of quantum-well layers and barriers.

Description

Light Emitting Device {LIGHT EMITTING DEVICE}

The present disclosure generally relates to a light emitting device, and more particularly, to a light emitting device having a low operating voltage and improved luminance.

The light emitting device includes a light emitting device including a compound semiconductor layer of Al (x) Ga (y) In (1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). It means a group III nitride light emitting device such as a diode, and does not exclude the inclusion of a material consisting of elements of other groups such as SiC, SiN, SiCN, CN or a semiconductor layer made of these materials.

This section provides background information related to the present disclosure which is not necessarily prior art.

1 is a view illustrating an example of a conventional Group III nitride semiconductor light emitting device, wherein the Group III nitride semiconductor light emitting device is grown on the substrate 10, the buffer layer 20 grown on the substrate 10, and the buffer layer 20. n-type group III nitride semiconductor layer 30, active layer 40 grown on n-type group III nitride semiconductor layer 30, p-type group III nitride semiconductor layer 50 grown on active layer 40, p-type 3 The p-side electrode 60 formed on the group nitride semiconductor layer 50, the p-side electrode pad 70 formed on the p-side electrode 60, the p-type group III nitride semiconductor layer 50 and the active layer 40 The n-side electrode 80 and the passivation layer 90 are formed on the n-type group III nitride semiconductor layer 30 exposed by mesa etching.

As the substrate 10, a GaN-based substrate is used as the homogeneous substrate, and a sapphire substrate, a SiC substrate, or a Si substrate is used as the heterogeneous substrate. Any substrate may be used as long as the group III nitride semiconductor layer can be grown. When a SiC substrate is used, the n-side electrode 80 may be formed on the SiC substrate side.

The group III nitride semiconductor layers grown on the substrate 10 are mainly grown by MOCVD (organic metal vapor growth method).

The buffer layer 20 is intended to overcome the difference in lattice constant and thermal expansion coefficient between the dissimilar substrate 10 and the group III nitride semiconductor, and US Pat. A technique for growing an AlN buffer layer having a thickness of US Pat. No. 5,290,393 describes Al (x) Ga (1-x) N having a thickness of 10 kPa to 5000 kPa at a temperature of 200 to 900 C on a sapphire substrate. (0 ≦ x <1) A technique for growing a buffer layer is described, and US Patent Publication No. 2006/154454 discloses growing a SiC buffer layer (seed layer) at a temperature of 600 ° C. to 990 ° C., followed by In (x Techniques for growing a Ga (1-x) N (0 <x≤1) layer are described. Preferably, the undoped GaN layer is grown prior to the growth of the n-type Group III nitride semiconductor layer 30, which may be viewed as part of the buffer layer 20 or as part of the n-type Group III nitride semiconductor layer 30. .

In the n-type group III nitride semiconductor layer 30, at least a region (n-type contact layer) in which the n-side electrode 80 is formed is doped with an impurity, and the n-type contact layer is preferably made of GaN and doped with Si. . U. S. Patent No. 5,733, 796 describes a technique for doping an n-type contact layer to a desired doping concentration by controlling the mixing ratio of Si and other source materials.

The active layer 40 is a layer that generates photons (light) through recombination of electrons and holes, and is mainly composed of In (x) Ga (1-x) N (0 <x≤1), and one quantum well layer (single quantum wells) or multiple quantum wells.

The p-type group III nitride semiconductor layer 50 is doped with an appropriate impurity such as Mg, and has an p-type conductivity through an activation process. U.S. Patent No. 5,247,533 describes a technique for activating a p-type group III nitride semiconductor layer by electron beam irradiation, and U.S. Patent No. 5,306,662 annealing at a temperature of 400 DEG C or higher to provide a p-type group III nitride semiconductor layer. A technique for activating is described, and US Patent Publication No. 2006/157714 discloses a p-type III-nitride semiconductor layer without an activation process by using ammonia and a hydrazine-based source material together as a nitrogen precursor for growth of the p-type III-nitride semiconductor layer. Techniques for having this p-type conductivity have been described.

The p-side electrode 60 is provided to ensure good current supply to the entire p-type group III nitride semiconductor layer 50. US Patent No. 5,563,422 is formed over almost the entire surface of the p-type group III nitride semiconductor layer. A light-transmitting electrode made of Ni and Au in ohmic contact with the p-type III-nitride semiconductor layer 50 is described. US Pat. No. 6,515,306 discloses n on the p-type III-nitride semiconductor layer. A technique is described in which a type superlattice layer is formed and then a translucent electrode made of indium tin oxide (ITO) is formed thereon.

On the other hand, the p-side electrode 60 can be formed to have a thick thickness so as not to transmit light, that is, to reflect the light toward the substrate side, this technique is referred to as flip chip (flip chip) technology. U. S. Patent No. 6,194, 743 describes a technique for an electrode structure including an Ag layer having a thickness of 20 nm or more, a diffusion barrier layer covering the Ag layer, and a bonding layer made of Au and Al covering the diffusion barrier layer.

The p-side electrode pad 70 and the n-side electrode 80 are for supplying current, and US Patent No. 5,563,422 describes a technique in which the n-side electrode is composed of Ti and Au.

The passivation layer 90 is formed of a material such as silicon dioxide and may be omitted.

Meanwhile, the n-type III-nitride semiconductor layer 30 or the p-type III-nitride semiconductor layer 50 may be composed of a single layer or a plurality of layers, and recently, the substrate 10 may be formed by laser or wet etching. A technique for manufacturing a vertical light emitting device by separating from group III nitride semiconductor layers has been introduced.

FIG. 2 is a diagram illustrating an example of a bandgap diagram of the active layer illustrated in FIG. 1.

As shown in FIG. 2, light emitting devices such as a light emitting diode (LED) and a laser diode (LD) emit light by converting electrical energy into light energy through a combination of electrons and holes in a quantum well layer constituting an active layer. Done. In this case, the efficient quantum efficiency of the light emitting device is determined by how efficiently the combination of electrons and holes occurs. In general, the thickness of the quantum well layer 41 and the barrier layers 42 and 44 constituting the active layer of the light emitting diode (LED) is configured to have a thickness that can minimize the piezoelectric field. For example, in the case of 6 cycles, the quantum well layer may have a thickness of 2.5 nm and the barrier layer may have a thickness of 5 nm, thereby forming a multi-quantum well structure.

In the case of the group III nitride semiconductor light emitting device, when compared with other compound semiconductors, the mobility (Mobility) of 10-20 is significantly lower than that of electrons (Mobility: 200-500), and thus in the active layer The mobility of holes greatly affects the performance of the light emitting device. Since mobility and conductivity are generally in direct relation, low hole mobility means that the electrical conductivity by holes is low. Therefore, in the Group III nitride semiconductor light emitting device, the electrical conductivity due to holes is low, and the light emitting device resistivity of the p-type nitride semiconductor layer is much larger than that of the n-type nitride semiconductor layer. Since the effective mass of the holes felt in the medium is higher than the electrons, the ratio injected into the quantum well layer becomes extremely small toward the n-type nitride semiconductor layer, for example, the n-GaN side. Therefore, only a few wells in contact with the p-type nitride semiconductor layer, for example, the p-GaN side, contribute to actual light emission, which makes it difficult to increase the brightness of light emitted from the light emitting device.

This will be described later in the Specification for Implementation of the Invention.

SUMMARY OF THE INVENTION Herein, a general summary of the present disclosure is provided, which should not be construed as limiting the scope of the present disclosure. of its features).

To this end, the present disclosure is an active layer which is located between an n-type nitride semiconductor layer, a p-type nitride semiconductor layer, an n-type nitride semiconductor layer and a p-type nitride semiconductor layer and generates light through recombination of electrons and holes, A barrier having a plurality of alternately stacked quantum well layers and barrier layers, the thickness of at least one thin barrier layer opposite the p-type nitride semiconductor layer immediately following the quantum well layer closest to the p-type nitride semiconductor layer Provided is a light emitting device comprising an active layer smaller than the thickness of the layers.

This will be described later in the Specification for Implementation of the Invention.

1 is a view showing an example of a conventional group III nitride semiconductor light emitting device,
FIG. 2 is a diagram illustrating an example of a bandgap diagram of the active layer illustrated in FIG. 1;
3 is a view showing an example of a light emitting device according to the present disclosure;
4 is a diagram illustrating an example of a bandgap diagram of an active layer illustrated in FIG. 3;
5 is a graph showing an example of distribution of holes injected from the p-GaN side in the multi-quantum well structure;
6 is a graph showing an operating voltage Vf of an example of a light emitting device according to the present disclosure;
7 is a graph showing luminance Iv of an example of a light emitting device according to the present disclosure;
8 is a graph showing an example of a bandgap diagram of another example of a light emitting device according to the present disclosure;
9 is a graph showing an example of a bandgap diagram of another example of a light emitting device according to the present disclosure;

The present disclosure will now be described in detail with reference to the accompanying drawing (s).

3 is a view illustrating an example of a light emitting device according to the present disclosure.

Referring to FIG. 3, an example of the light emitting device according to the present disclosure may be substantially the same as the light emitting device described in FIG. 1 except for the structure of the active layer 240. Therefore, the structure of the active layer 240 will be described.

In the present disclosure, in order to improve the recombination efficiency of electrons and holes to improve the brightness of the light emitting device, an improvement point in view of the mobility of holes has been devised. The diffusion length of the carrier (hole) from the p-type nitride semiconductor layer 250 tends to be shorter than that of the carrier (electron) from the n-type nitride semiconductor layer 230. Accordingly, in the present disclosure, the holes reaching the n-type nitride semiconductor layer 230 from the p-type nitride semiconductor layer 250 to the active layer 240 are increased to increase the efficiency of electron and hole recombination. To this end, the thickness of at least one thin barrier layer located opposite the p-type nitride semiconductor layer 250 immediately after the quantum well layer closest to the p-type nitride semiconductor layer 250 is smaller than the thickness of the other barrier layers. do. The structure of the active layer 240 will be described later in detail.

A buffer layer or seed layer 220, an n-type nitride semiconductor layer 230, a quantum well layer of nitride semiconductor, and a barrier layer serving as a seed of growth on a substrate 210 such as sapphire or SiC. The active layer 240 and the p-type nitride semiconductor layer 250 are sequentially stacked to form a light emitting device. Each layer may again include sublayers as needed. The n-side electrode 280 is formed on the etched n-type nitride semiconductor layer 230, and the p-side electrode 260 and the p-side bonding pad 270 are formed on the p-type nitride semiconductor layer 250. The protective film 290 is formed on the top. When the SiC substrate is used, the n-side electrode 280 may be formed under the substrate 210.

The barrier layer and the quantum well layer are alternately stacked on the n-type nitride semiconductor layer 230 to form the active layer 240. For example, starting from the P-type nitride semiconductor layer 250, the B1 barrier layer to the Bn barrier layer and the W1 quantum well layer to the (Wn-1) quantum well layer are alternately stacked. Of course, the barrier layer may be composed of multiple layers of two or more layers as necessary, and Bi described herein means all of the multilayers when the barrier layer is composed of multiple layers.

4 is a diagram illustrating an example of a bandgap diagram of the active layer illustrated in FIG. 3.

3 and 4, at least one thin barrier layer located opposite the p-GaN layer immediately after the p-nitride semiconductor layer 250, eg, the W1 quantum well layer closest to the p-GaN layer. The thickness of 241 is smaller than the thickness of other barrier layers to improve the diffusion into the active layer 240 of the holes.

As shown in FIG. 4, an active layer 240 having six quantum well layers is configured, and band gap energy of a conduction band (Ec) and a valence band (Ev) is illustrated.

For example, the layer disposed closest to the n-GaN layer and the p-GaN layer may be a barrier layer, and the W1 quantum well layer is the quantum well layer closest to the p-GaN layer. The B1 barrier layer is formed between the W1 quantum well layer and the p-GaN layer and is a p-side barrier layer in contact with the p-GaN layer. The thickness and composition are controlled to prevent impurities from diffusing from the p-GaN layer into the active layer 240. Can be. Thus, the at least one thin barrier layer 241 corresponds to a barrier layer located opposite the p-GaN layer immediately after the W1 quantum well layer, and thus may be one B2 barrier layer or several, for example, starting from the B2 barrier layer. For example, it may include two to three or more barrier layers.

In FIG. 4, an example of at least one thin barrier layer 241 is one B2 barrier layer. One thin barrier layer 241 is formed between the W1 quantum well layer and the W2 quantum well layer. The remaining quantum well layers and barrier layers are formed between the W2 quantum well layer and the n-type nitride semiconductor layer, for example the n-GaN layer.

The thin barrier layer 241 is formed to a smaller thickness than the other barrier layers. For example, the thickness of the thin barrier layer 241 may be 0.1 to 0.9 times the thickness of the B1, B3, B4, B5, B6 barrier layer thickness. More preferably, they are 0.1 times or more and 0.8 times or less. If the thickness of the thin barrier layer 241 is less than 0.1 times the thickness of the other barrier layers, the barrier function may be degraded and two adjacent well layers may overlap. If the thickness of the thin barrier layer 241 exceeds 0.8 times the thickness of other barrier layers, the improvement of the hole injection effect may be insignificant.

Holes injected into the p-GaN layer diffuse into the thin barrier layer 241 through the B1 barrier layer. The thin barrier layer 241 is formed to a smaller thickness than the other barrier layers, thereby reducing the thickness of the physical layer that holes must pass through to diffuse deep into the active layer 240. Therefore, the diffusion length of holes increases in the active layer 240, and the number of quantum well layers to which electrons and holes are recombined is not limited to a few quantum well layers adjacent to the p-GaN layer. As a result, the quantum well layer from which light is substantially increased increases the luminance of the light emitting device.

5 is a graph showing an example of distribution of holes injected from the p-GaN side in the multi-quantum well structure.

The light emitting device of the comparative example shown in FIG. 5 is a light emitting device substantially the same as the light emitting device described in FIGS. 1 and 2, and as shown in FIG. 2, the thickness of the barrier layer adjacent to the p-GaN layer is different from that of the other barrier layers. It was formed to be substantially equal to the thickness. The quantum well layer 41 has a thickness of 2.5 nm and the barrier layers 42 and 44 have a thickness of 5 nm to form a multi-quantum well structure.

Considering the characteristics of GaN and its piezoelectric field, the distribution of carriers (holes) injected into the p-GaN layer when simulating the light emitting device of the comparative example under 300K and 6V forward bias conditions. Results are shown in FIG. 5 (see APL 93, 171113 (2008), X. Ni, Q. Fan, R. Shimada, U. Ozgur, H. Morkoc).

In FIG. 5, the horizontal axis represents the distance from the p-GaN layer to the n-GaN layer, and the horizontal axis of 0.00 um corresponds to the surface of the p-GaN layer in contact with the active layer 40, and the 0.20 um point is in contact with the active layer 40. It corresponds to the n-GaN layer surface. The left vertical axis represents the energy level of the energy band. The multi-quantum well structure of the active layer 40 is shown by conduction band Ec and valence band Ev. The right vertical axis represents the concentration of carriers, ie holes, injected into the p-GaN layer. Graph G1 is a graph showing the distribution of holes in the active layer 40 of the comparative example described above.

Referring to graph G1, hole concentrations range from approximately 10 ¹⁸ to several quantum well layers adjacent to the p-GaN layer. It can be seen that while maintaining a concentration of about 10 ¹⁹ , the hole rapidly decreases from the position of about 0.04um from the p-GaN layer and diffuses to the vicinity of the n-GaN layer. This indicates that since the hole mobility of the nitride semiconductor is very low, holes do not easily pass through the barrier layer, and significant diffusion only occurs to some quantum well layers adjacent to the p-GaN layer. Therefore, the quantum well layer in which light is generated by combining electrons and holes is limited to a few quantum well layers adjacent to the p-GaN layer, making it difficult to increase the luminance of the light emitting device by a certain degree or more.

6 is a graph showing an operating voltage Vf of an example of a light emitting device according to the present disclosure.

In order to confirm the characteristics of the light emitting device according to the present disclosure, experiments were conducted on various samples of the light emitting device according to the present disclosure. In one example of the light emitting device according to the present disclosure, the quantum well layer W1 ... Wn is a nitride semiconductor containing In, more preferably In (x) Ga (1-x) N (0≤x By using ≤1), a good element life can be obtained. Barrier layer (B1, ..., Bn) can also be formed using In (x) Ga (1-x) N (0≤x≤1), the barrier layer is less than x or x than the quantum well layer May be = 0. For example, the quantum well layer may be formed with 0.10 <x <0.30, and the barrier layer including the thin barrier layer 241 may be formed with 0 <x <0.10. The barrier layer may be doped with n-type impurities such as Si, and the quantum well layer may not be doped with impurities. The dope or not, the type of dope, the concentration of the dope and the like for the thin barrier layer 241 may be appropriately selected to effectively diffuse holes and recombine electrons and holes.

In general, the thicknesses of the quantum well layer and the barrier layer constituting the active layer 240 may be configured to have a thickness that minimizes the piezoelectric field. In the present disclosure, the thickness of the thin barrier layer 241 immediately after the W1 quantum well layer closest to the p-GaN layer may improve the extent to which holes are diffused through the thin barrier layer 241 as described above. 241 may be appropriately selected so that recombination of electrons and holes occurs effectively in both W1 and W2 quantum well layers.

In one example of the light emitting device according to the present disclosure, for example, the B1, B3, B4, B5 and B6 barrier layers except for the thin barrier layer 241 are each formed about 12 nm thick, and the W1 quantum well layer and Quantum well layers, including the W2 quantum well layer, were each formed about 3 nm thick. The thin barrier layer 241 is formed to have a smaller thickness than the other barrier layers.

In FIG. 6, the horizontal axis represents various samples in one example of the light emitting device according to the present disclosure. The samples are substantially identical in other configurations except for the thickness of the thin barrier layer 241. The vertical axis represents the operating voltage Vf of the light emitting device, and the unit is volts (V). Experimental results are indicated by dots in FIG. 6, and when the 20 mA is applied, the light emitting device of the comparative example described in FIG. 5 is represented by ref, and the samples of one example of the light emitting device according to the present disclosure are sample identification marks QB23-40%, and the like. Is indicated.

Referring to the experimental result illustrated in FIG. 6, since all the samples of the light emitting device according to the present disclosure are located below the light emitting device of the comparative example, it can be seen that the operating voltage is lowered. When the thickness of the thin barrier layer 241 is approximately 0.1 to 0.8 times the thickness of the other barrier layer, the operation voltage is significantly lowered. In particular, when the thickness of the thin barrier layer 241 is approximately 0.2 times or more than 0.6 times the thickness of the other barrier layer, the effect of lowering the operating voltage is remarkable, and it can be seen that there is an operating voltage drop effect of approximately 0.05V than the light emitting device of the comparative example. there was.

7 is a graph showing luminance Iv of an embodiment of a light emitting device according to the present disclosure.

In FIG. 7, the horizontal axis represents various samples in one example of the light emitting device according to the present disclosure. The samples are substantially identical in other configurations except for the thickness of the thin barrier layer 241. The thickness of the thin barrier layer 241 of the samples was formed smaller than the thickness of the other barrier layers. The vertical axis represents the luminance Iv of the light emitting device, and the unit is milliwatts (mW).

Referring to FIG. 7, luminance of samples of an example of the light emitting device according to the present disclosure is indicated by dots above the light emitting device ref of the comparative example. Therefore, it can be seen that the light emitting device according to the present disclosure has higher luminance than the light emitting device of the comparative example and thus the brightness is improved. When the thickness of the thin barrier layer 241 is approximately 0.1 to 0.8 times the thickness of the other barrier layer, the operating voltage significantly improved the brightness. In particular, when the thickness of the thin barrier layer 241 is approximately 0.2 times or more than 0.6 times the thickness of the other barrier layer, the effect of improving the brightness is remarkable, and the brightness of the comparative example is about 5% to 6%.

Referring to the simulation results described with reference to FIG. 5 and the experimental results described with reference to FIGS. 6 and 7, one example of the light emitting device according to the present disclosure is that the diffusion length of maintaining a hole concentration of about 10 ¹⁷ or more is increased than that of the light emitting device of the comparative example. It seems to be. Therefore, in the light emitting device according to the present disclosure, holes injected into the p-GaN layer are diffused deeper into the active layer 240 than the light emitting device of the comparative example due to the thin barrier layer 241 adjacent to the p-GaN layer. It is determined that the operating voltage is reduced and the brightness is improved.

8 is a graph illustrating an example of a bandgap diagram of another example of a light emitting device according to the present disclosure. 9 is a graph illustrating an example of a bandgap diagram of another example of a light emitting device according to the present disclosure.

8 and 9 are substantially the same as the light emitting device described with reference to FIGS. 3 to 7 except for a plurality of thin barrier layers. 8 and 9, three thin barrier layers B2, B3, and B4 are opposite to the p-GaN (450, 650) layer immediately after the quantum well layer W1 closest to the p-GaN layers 450, 650. Located in

The thin barrier layers B2, B3 and B4 have the same thickness as shown in FIG. 8 and may be smaller than the other barrier layers B5 and B6. Alternatively, the thin barrier layers B2, B3, and B4 become thicker from the quantum well layer W1 closest to the p-GaN 650 layer toward the n-GaN side, as shown in FIG. It may be smaller than B5 and B6).

8 and 9, the thickness of the thin barrier layers B2, B3, B4 is about 0.1 to 0.8 times the thickness of the other barrier layers B5 and B6, more preferably about 0.2 to 0.6 times.

According to the light emitting device according to the present disclosure illustrated in FIGS. 8 and 9, the number of thin barrier layers is selected according to the characteristics of the quantum wells of the active layer, and the thickness of the thin barrier layer is from the thin barrier layer close to the p-GaN layer. By changing gradually, the hole injection efficiency can be improved.

Hereinafter, various embodiments of the present disclosure will be described.

(1) The light emitting element according to claim 1, wherein the number of at least one thin barrier layer is three or less.

If there are at least two thin barrier layers positioned opposite the p-type nitride semiconductor layer immediately after the quantum well layer closest to the p-type nitride semiconductor layer, the thin barrier layers have a smaller thickness than the other barrier layers, but are thinner. The barrier layers may differ in thickness from each other.

(2) One thin barrier layer is located between the quantum well layer closest to the p-type nitride semiconductor layer and the second closest quantum well layer, and is located between the second closest quantum well layer and the n-type nitride semiconductor layer. Light emitting device having a smaller thickness than other barrier layers.

(3) A light emitting element comprising at least two thin barrier layers and the same thickness as each other.

(4) A light emitting device comprising at least two thin barrier layers and different thicknesses from each other.

(5) A light emitting device characterized in that the thickness of the thin barrier layer is 0.1 to 0.8 times the thickness of the other barrier layers.

(6) A light emitting element characterized in that the thickness of the thin barrier layer is not less than 0.2 times and not more than 0.6 times the thickness of the other barrier layers.

(7) A light emitting element, wherein the thickness of the other barrier layer is 11 nm or more and 13 nm or less, and the thickness of the quantum well layer is 2.5 nm or more and 3.5 nm or less.

(8) A light emitting element comprising a p-side barrier layer positioned between the quantum well layer closest to the p-type nitride semiconductor layer and the p-type nitride semiconductor layer and in contact with the p-type nitride semiconductor layer.

(9) A light emitting element characterized in that the thickness of the thin barrier layer is smaller than the thickness of the p-side barrier layer.

According to the light emitting device according to the present disclosure, the diffusion length of holes into the active layer is increased, so that an operating voltage of the light emitting device is reduced and luminance is improved.

210: substrate 220: buffer layer
230: n-type nitride semiconductor layer 240: active layer
B1, ..., Bn: barrier layer W1, ..., Wn: quantum well layer
241 thin barrier layer 250 p-type nitride semiconductor layer

Claims (10)

an n-type nitride semiconductor layer;
p-type nitride semiconductor layer; And
an active layer positioned between the n-type nitride semiconductor layer and the p-type nitride semiconductor layer and generating light through recombination of electrons and holes, the p-type nitride layer having a plurality of alternating quantum well layers and barrier layers; And an active layer having a thickness of at least one thin barrier layer located opposite to the p-type nitride semiconductor layer immediately after the quantum well layer closest to the nitride semiconductor layer, which is smaller than the thicknesses of the other barrier layers. The method according to claim 1,
The number of at least one thin barrier layer is less than three light emitting device. The method according to claim 2,
One thin barrier layer is located between the quantum well layer closest to the p-type nitride semiconductor layer and the second closest quantum well layer, and the other barrier layer is located between the second closest quantum well layer and the n-type nitride semiconductor layer. Light emitting device having a thickness smaller than those. The method according to claim 2,
At least one thin barrier layer is two or more, the light emitting device, characterized in that the same thickness with each other. The method according to claim 2,
A light emitting device comprising at least two thin barrier layers and different thicknesses. The method according to claim 1,
The thickness of the thin barrier layer is a light emitting device, characterized in that more than 0.1 times 0.8 times the thickness of the other barrier layers. The method of claim 6,
The thickness of the thin barrier layer is a light emitting device, characterized in that more than 0.2 times 0.6 times the thickness of the other barrier layers. The method of claim 6,
The thickness of the other barrier layer is 11 nm or more and 13 nm or less, and the thickness of the quantum well layer is 2.5 nm or more and 3.5 nm or less. The method according to claim 1,
and a p-side barrier layer positioned between the quantum well layer closest to the p-type nitride semiconductor layer and the p-type nitride semiconductor layer and in contact with the p-type nitride semiconductor layer. The method according to claim 9,
The thickness of the thin barrier layer is smaller than the thickness of the p-side barrier layer.

Images