JP4069479B2 - Multiple quantum well semiconductor light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor light emitting device, and more particularly, is suitable for use in a semiconductor laser having a multiple quantum well (MQW) structure having three or more wells.
[0002]
[Prior art]
In order to improve the characteristics of the semiconductor laser, it is extremely effective to make the active layer part a quantum well (QW) structure. Because the half-width of the optical gain spectrum is narrowed due to the step-like state density function, and the maximum gain value is increased, the threshold current is lowered and the electron energy distribution is less susceptible to temperature fluctuations. Temperature characteristics are improved (T ₀ is increased). In addition, effects such as shortening of the laser oscillation wavelength, anisotropic gain, stability of the oscillation spectrum, and low loss as a waveguide can be obtained.
[0003]
Because of these characteristics, the quantum well structure has been carefully designed to further improve the characteristics. For example, in order to increase the energy difference between the lowest miniband and the next miniband in a quantum well, the barrier layer is made thicker or the barrier layer is made higher to weaken the coupling between the wells. However, the carrier injection cannot be made uniform, and it is necessary to design for the oscillation wavelength.
[0004]
It is important that the multi-quantum well structure designed in this way be as uniform as possible, and the thickness and composition ratio of the well and the thickness and composition ratio of the barrier layer are the same in one light emitting device. I let you.
[0005]
However, there is no problem with a single quantum well structure (SQW) composed of one QW or a quantum well structure composed of two QWs. The evaluation of the growth film shows that the confinement of carriers and light is different between the quantum well located at the end and the quantum well located at the end, which is the cause of non-uniform emission characteristics.
[0006]
[Problems to be solved by the invention]
Therefore, according to the present invention, in a semiconductor light emitting device having a multiple quantum well structure, light emission nonuniformity is prevented from occurring due to a difference in confinement of carriers and light depending on the position of the quantum well.
[0007]
[Means for Solving the Problems]
The present invention has been made in view of such problems, and a multiple quantum well semiconductor light emitting device of the present invention includes at least a first conductivity type first cladding layer and a first cladding layer on a compound semiconductor substrate. an active layer portion having three or more quantum wells formed in the upper, Te semiconductor light emitting element odor of a second cladding layer of a second conductivity type provided on the active layer portion, the center of the active layer portion The quantum well of the portion is configured to be thinner than the quantum well adjacent to the cladding layer which is the end portion of the active layer portion.
Further, on the compound semiconductor substrate, at least a first conductivity type first cladding layer, a light guide layer provided on the first cladding layer, and three or more quantum wells provided on the light guide layer an active layer portion having a light guide layer provided on the active layer section, Te semiconductor light emitting element odor of a second cladding layer of a second conductivity type provided on the light guide layer, the active layer portion The quantum well at the center of each is characterized in that it is thinner than the quantum well adjacent to the guide layer which is the end of the active layer portion.
[0008]
In addition, the multiple quantum well semiconductor device of the present invention has at least a first conductivity type first cladding layer and three or more quantum wells provided on the first cladding layer on a compound semiconductor substrate. an active layer portion, in the semiconductor light emitting device comprising a second cladding layer of a second conductivity type provided on the active layer portion of a quantum well in the central portion of the active layer section, the energy gap that is configured to uniformly mutually Is characterized by being configured to be larger than the energy gap in the quantum well adjacent to the cladding layer, which is the end of the active layer portion.
Further, on the compound semiconductor substrate, at least a first conductivity type first cladding layer, a light guide layer provided on the first cladding layer, and three or more quantum wells provided on the light guide layer an active layer portion having a light guide layer provided on the active layer portion, in the semiconductor light emitting device comprising a second cladding layer of a second conductivity type provided on the light guide layer, the active layer portion The energy gap of the quantum well in the central part, which is configured uniformly with each other , is configured to be larger than the energy gap in the quantum well adjacent to the cladding layer at the end of the active layer part.
[0009]
The multiple quantum well semiconductor device of the present invention has an active layer having at least a first conductivity type first clad layer and three or more barriers provided on the first clad layer on a compound semiconductor substrate. parts and, in the semiconductor light emitting device comprising a second cladding layer of a second conductivity type provided on the active layer section, a barrier that is configured to mutually uniform thickness of the central portion of the active layer portion, the active layer It is characterized in that it is thicker than the barrier adjacent to the cladding layer, which is the end of the part.
Further, on the compound semiconductor substrate, at least a first conductivity type first cladding layer, a light guide layer provided on the first cladding layer, and three or more barriers provided on the light guide layer are provided. an active layer portion having a light guide layer provided on the active layer portion, in the semiconductor light emitting device comprising a second cladding layer of a second conductivity type provided on the light guide layer, the center of the active layer portion The barriers configured to have a uniform thickness in each part are configured to be thicker than the barrier adjacent to the guide layer, which is the end of the active layer part.
[0010]
Furthermore, the multiple quantum well semiconductor device of the present invention has an active having at least a first conductivity type first cladding layer and three or more barriers provided on the first cladding layer on a compound semiconductor substrate. a layer portion, in the semiconductor light emitting device comprising a second cladding layer of a second conductivity type provided on the active layer portion, the barrier of the central portion of the active layer section, the energy gap constructed uniformly with each other, It is characterized by being configured to be larger than the energy gap in the barrier adjacent to the cladding layer, which is the end of the active layer.
Further, on the compound semiconductor substrate, at least a first conductivity type first cladding layer, a light guide layer provided on the first cladding layer, and three or more barriers provided on the light guide layer are provided. an active layer portion having a light guide layer provided on the active layer portion, in the semiconductor light emitting device comprising a second cladding layer of a second conductivity type provided on the light guide layer, the center of the active layer portion The energy gaps of the barriers of the part that are uniformly configured with respect to each other are larger than the energy gaps of the barriers adjacent to the guide layer at the end of the active layer part.
[0011]
By adopting the above-described configuration, the confinement of carriers and light in the quantum well layer located at the center and the quantum well layers at both ends adjacent to the cladding layer exactly match each other, and uniform light emission characteristics can be obtained.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to FIGS. 1 to 6 are diagrams for explaining means for solving the problems of the present invention. FIG. 1 shows a PL (photoluminescence) peak of a single quantum well, and FIG. 2 shows a PL peak of two quantum wells. 3 shows the PL peak of three or more quantum wells, FIG. 4 shows the PL peak of the structure grown by changing the thickness of the three quantum wells, and FIG. 5 shows the three quantum wells. The PL peak of another structure grown by changing the thickness of the well is shown. FIG. 6 is a schematic sectional view of an example of an AlGaInP semiconductor laser according to the present invention. Further, FIGS. 7 to 14 are schematic cross-sectional views showing the structure of the active layer portion of the AlGaInP-based semiconductor laser according to the first to eighth embodiments.
[0013]
In order to solve the above-mentioned problems, the present inventors have developed a quantum well structure composed of ZnCdSe, ZnSSe, ZnMgSSe using ZnCdSe as a light emitting layer using a II-VI group compound semiconductor, and InGaP using a group III-V compound semiconductor. A quantum well structure made of InGaP and AlGaInP having a light-emitting layer as a light-emitting layer was grown, and optical characteristics were evaluated by PL.
[0014]
First, in the structure having one quantum well, the PL peak obtained as a result of the measurement was symmetrical as shown in FIG. Further, even in the structure having two quantum wells, the PL peak obtained as a result of the measurement was symmetrical as shown in FIG. However, in the structure having three or more quantum wells, the PL peak has a shape with a tail on the short wavelength side as shown in FIG.
[0015]
Furthermore, the present inventors fabricated two types of quantum well structures, a quantum well located at the end of the quantum well being two monolayers thicker than a quantum well located at the center, and a layer thinner by two monolayers. The PL peak was measured. As a result, the two monolayer thick layers were symmetrical as shown in FIG. 4, whereas the two monolayer thin layers have a large skirt on the short wavelength side as shown in FIG. It became.
[0016]
From these facts, it can be seen that the skirt on the short wavelength side is related to the structure of the end portion of the quantum well in the PL peak having the wavelength on the horizontal axis and the PL emission intensity on the vertical axis. Therefore, by utilizing this phenomenon, it is possible to design a quantum well capable of obtaining a PL peak having excellent PL emission characteristics and a small half width.
Next, an embodiment of an AlGaInP semiconductor laser manufactured based on this viewpoint will be described.
[0017]
First Embodiment FIG. 6 is a cross-sectional view of a group III-V compound semiconductor laser which is a first embodiment of the present invention, and this structure is formed by metal organic chemical vapor deposition (MOCVD). It is produced by. In this example, an n-type GaAs buffer layer 2 having a thickness of 0.3 μm, an n-type AlGaInP cladding layer 3 having a thickness of 1 μm, an active layer 4 having a GaInP / AlGaInPMQW structure, and a p-type AlGaInP having a thickness of 1 μm are formed on an n-type GaAs substrate 1. A cladding layer 5, a p-type GaInP layer 6 having a thickness of 0.1 μm, and a p-type GaAs cap layer 7 having a thickness of 0.3 μm are sequentially grown.
[0018]
Next, the p-type AlGaInP cladding layer 5, the p-type GaInP layer 6, and the p-type GaAs cap layer 7 are selectively etched using, for example, photolithography to form a mesa structure, and then an n-type GaAs current blocking layer 8 is grown and stacked on both sides of the mesa structure. As the dopant, the n-type is Se or Si, and the p-type is Zn.
[0019]
As shown in FIG. 7, the structure of the active layer 4 in FIG. 6 is an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, A 50-inch thick (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 10, a 40 _0.5- thick Ga _0.52 In _0.48 P quantum well layer 11, and a 46-thick Ga _0.52 In _0.48 P quantum well near the cladding layer It consists of layer 12. The number of well layers is five.
[0020]
According to the first embodiment, a semiconductor laser having excellent emission characteristics is obtained because the confinement of carriers and light in the quantum well layer located in the center and the quantum well layer located adjacent to the cladding layer exactly match each other. Can be realized.
[0021]
Second Embodiment Example The second embodiment example is the same as the first embodiment except for the structure of the active layer 4.
As shown in FIG. 8, the active layer 4 includes an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, and a 300-inch thick n-type. (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 13, 300 Å thick p-type (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 14, and 50 Å thick (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 15, a Ga _0.52 In _0.48 P quantum well layer 16 located in the center of 40 Å thickness, and a Ga _0.52 In _0.48 P quantum well layer 17 near the cladding layer of 43 Å thickness. The number of well layers is five.
[0022]
According to the second embodiment, since the confinement of carriers and light in the quantum well layer located at the center and the quantum well layer located adjacent to the guide layer exactly match each other, the semiconductor laser having excellent emission characteristics can be obtained. Can be realized.
[0023]
Third Embodiment Example The third embodiment example is the same as the first embodiment except for the structure of the active layer 4.
As shown in FIG. 9, the active layer 4 includes an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, and a 50 mm thick (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 18, (Al _0.03 Ga _0.97 ) _0.52 In _0.48 P quantum well layer 19 located in the center of 40 Å thickness, and Ga _0.52 In _0.48 P quantum well near the 40 Å thickness cladding layer Layer 20. The number of well layers is five.
[0024]
According to the third embodiment, since the confinement of carriers and light in the quantum well layer located at the center and the quantum well layer located adjacent to the clad layer exactly match each other, a semiconductor laser having excellent emission characteristics can be obtained. Can be realized.
[0025]
Fourth embodiment example Except for the structure of the active layer 4, the fourth embodiment example is the same as the first embodiment example.
As shown in FIG. 10, the active layer 4 includes an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, and a 300-inch thick n-type. (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 13, 300 Å thick p-type (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 14, and 50 Å thick (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 21 and (Al _0.03 Ga _0.97 ) _0.52 In _0.48 P quantum well layer 22 located in the center of 40 Å thickness and Ga _0.52 In _0.48 P quantum well layer 23 near the 40 Å thickness cladding layer. The number of well layers is five.
[0026]
According to the fourth embodiment, since the confinement of carriers and light in the quantum well layer located in the center and the quantum well layer located adjacent to the guide layer exactly match, a semiconductor laser having excellent emission characteristics can be obtained. Can be realized.
[0027]
Fifth embodiment Example The fifth embodiment is the same as the first embodiment except for the structure of the active layer 4.
As shown in FIG. 11, the active layer 4 has an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, and has a thickness of 80 mm. The (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 24 and the (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 25 located close to the 50-thick cladding layer, and 40-thick Ga _0.52 In _0.48 P It consists of a quantum well layer 26. The number of well layers is five.
[0028]
According to the fifth embodiment, since the confinement of carriers and light in the quantum well layer located in the center and the quantum well layer located adjacent to the clad layer exactly coincide, Can be realized.
[0029]
Sixth embodiment The same as the first embodiment except for the structure of the active layer 4.
As shown in FIG. 12, the active layer 4 includes an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, and a 300-inch thick n-type. (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 13, 300 mm thick p-type (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 14 and 80 mm thick centered (Al _0.35 Ga _0.65 ) _0.5 In _It consists of a _0.5 P barrier layer 27, a (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 28 and a 40 _0.5- thick Ga _0.52 In _0.48 P quantum well layer 29 located close to the 50-thick clad layer. The number of well layers is five.
[0030]
According to the sixth embodiment, since the confinement of carriers and light in the quantum well layer located at the center and the quantum well layer located adjacent to the guide layer exactly match each other, a semiconductor laser having excellent emission characteristics can be obtained. Can be realized.
[0031]
Seventh embodiment Example The seventh embodiment is the same as the first embodiment except for the structure of the active layer 4.
As shown in FIG. 13, the active layer 4 includes an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, and a thickness of 50 mm. The (Al _0.5 Ga _0.5 ) _0.5 In _0.5 P barrier layer 30 located, the (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 31 located close to the 50-thick cladding layer, and the 40 _0.5- thick Ga _0.52 In _0.48 P It consists of a quantum well layer 32. The number of well layers is five.
[0032]
According to the seventh embodiment, since the confinement of carriers and light in the quantum well layer located in the center and the quantum well layer located adjacent to the clad layer exactly match each other, the semiconductor laser having excellent emission characteristics can be obtained. Can be realized.
[0033]
Eighth Embodiment Example The eighth embodiment example is the same as the first embodiment except for the structure of the active layer 4.
As shown in FIG. 14, the active layer 4 includes an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 3, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 5, and a 300-inch thick n-type. (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 13, p-type (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P guide layer 14 having a thickness of 300 mm, and (Al _0.5 Ga _0.5 ) _0.5 In located in the center of 50 mm thickness _It consists of a _0.5 P barrier layer 33, a (Al _0.35 Ga _0.65 ) _0.5 In _0.5 P barrier layer 34 and a 40 _0.5 thick Ga _0.52 In _0.48 P quantum well layer 35 located close to the 50-thick cladding layer. The number of well layers is five.
[0034]
According to the eighth embodiment, since the confinement of carriers and light in the quantum well layer located in the center and the quantum well layer located adjacent to the guide layer exactly match, a semiconductor laser having excellent light emission characteristics can be obtained. Can be realized.
[0035]
The first to eighth embodiments have been described above, but the present invention is not limited to these embodiments, and various modifications and combinations based on the technical idea of the present invention are possible. Needless to say.
For example, an AlGaInP semiconductor laser that is a III-V compound semiconductor is grown by MOCVD, but a ZnSe semiconductor laser that is a II-VI compound semiconductor can also be grown by molecular beam epitaxy (MBE).
The present invention can also be applied to light emitting diodes.
[0036]
【The invention's effect】
As is apparent from the above description, according to the present invention, in a semiconductor laser having a multiple quantum well structure having three or more wells, one or more quantum well layers in the center and two at both ends adjacent to the cladding layer are provided. The thickness of the quantum well layers is not the same, or the energy gaps of one or more quantum well layers in the center and the two quantum well layers at both ends adjacent to the cladding layer are not the same, or The carrier and light in the quantum well layer located at the center and the quantum well layers at both ends adjacent to the cladding layer are not made the same by making the energy gap of the two barrier layers adjacent to the cladding layer equal to or more than one barrier layer. Therefore, it is possible to realize a semiconductor light emitting device having excellent light emission characteristics.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a PL peak of a single quantum well for explaining means for solving the problems.
FIG. 2 is a schematic diagram showing PL peaks of two quantum wells for explaining means for solving the problems.
FIG. 3 is a schematic diagram showing PL peaks of three or more quantum wells for explaining means for solving the problems.
FIG. 4 is a schematic diagram showing a PL peak of a structure grown by changing the thickness of three quantum wells, for explaining means for solving the problem.
FIG. 5 is a diagram for explaining a means for solving the problem, and is a schematic diagram showing a PL peak of a structure grown by changing the thickness of three quantum wells;
FIG. 6 is a schematic sectional view of an example of an AlGaInP based semiconductor laser according to the present invention.
FIG. 7 is a schematic cross-sectional view showing the structure of the active layer portion of the AlGaInP-based semiconductor laser that is the first embodiment according to the present invention.
FIG. 8 is a schematic sectional view showing a structure of an active layer portion of an AlGaInP-based semiconductor laser which is a second embodiment according to the present invention.
FIG. 9 is a schematic sectional view showing a structure of an active layer portion of an AlGaInP based semiconductor laser which is a third embodiment according to the present invention.
FIG. 10 is a schematic cross-sectional view showing the structure of an active layer portion of an AlGaInP-based semiconductor laser that is a fourth embodiment according to the present invention.
FIG. 11 is a schematic sectional view showing the structure of an active layer portion of an AlGaInP based semiconductor laser which is a fifth embodiment according to the present invention.
FIG. 12 is a schematic cross-sectional view showing the structure of the active layer portion of an AlGaInP-based semiconductor laser that is a sixth embodiment according to the present invention.
FIG. 13 is a schematic sectional view showing the structure of an active layer portion of an AlGaInP based semiconductor laser which is a seventh embodiment according to the present invention.
FIG. 14 is a schematic sectional view showing the structure of an active layer portion of an AlGaInP-based semiconductor laser that is an eighth embodiment according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... n-type GaAs substrate, 2 ... n-type GaAs buffer layer, 3 ... n-type AlGaInP clad layer, 4 ... Active layer, 5 ... p-type AlGaInP clad layer, 6 ... p-type GaInP layer, 7 ... p-type GaAs cap layer , 8... N-type GaAs current blocking layer, 10, 15, 18, 21, 24, 25, 27, 28, 30, 31, 33, 34... AlGaInP barrier layer, 11, 12, 16, 17, 20, 23, 26, 29, 32, 35 ... GaInP quantum well layer, 13 ... n-type AlGaInP guide layer, 14 ... p-type AlGaInP guide layer, 19, 22 ... AlGaInP quantum well layer

Claims (8)

On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
An active layer portion having three or more quantum wells provided on the first cladding layer;
In the semiconductor light emitting device comprising the second conductivity type second clad layer provided on the active layer portion,
The multi-quantum well semiconductor light emitting device, wherein the quantum well in the central portion of the active layer portion is configured to be thinner than the quantum well that is an end portion of the active layer portion and is adjacent to the cladding layer. On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
A light guide layer provided on the first cladding layer;
An active layer portion having three or more quantum wells provided on the light guide layer;
A light guide layer provided on the active layer portion;
In the semiconductor light emitting device comprising the second conductivity type second cladding layer provided on the light guide layer,
The multi-quantum well semiconductor light emitting device, wherein the quantum well in the central portion of the active layer portion is configured to be thinner than a quantum well that is an end portion of the active layer portion and is adjacent to the guide layer. On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
An active layer portion having three or more quantum wells provided on the first cladding layer;
In the semiconductor light emitting device comprising the second conductivity type second clad layer provided on the active layer portion,
The energy gaps of the quantum wells in the central part of the active layer part , which are configured uniformly with each other, are configured to be larger than the energy gaps in the quantum wells that are the end parts of the active layer part and adjacent to the cladding layer. A multi-quantum well semiconductor light emitting device characterized by the above. On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
A light guide layer provided on the first cladding layer;
An active layer portion having three or more quantum wells provided on the light guide layer;
A light guide layer provided on the active layer portion;
In the semiconductor light emitting device comprising the second conductivity type second cladding layer provided on the light guide layer,
The energy gaps of the quantum wells in the central part of the active layer part that are uniformly formed are larger than the energy gaps in the two quantum wells that are the end parts of the active layer part and adjacent to the cladding layer. A multi-quantum well semiconductor light emitting device characterized in that On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
An active layer portion having three or more barriers provided on the first cladding layer;
In the semiconductor light emitting device comprising the second conductivity type second clad layer provided on the active layer portion,
Multiple quantum barrier configured in mutually uniform thickness of the central portion of the active layer portion, characterized in that it is configured thicker than the adjacent barrier to the active layer portion and the clad layer is an end portion of the Well type semiconductor light emitting device. On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
A light guide layer provided on the first cladding layer;
An active layer portion having three or more barriers provided on the light guide layer;
A light guide layer provided on the active layer portion;
In the semiconductor light emitting device comprising the second conductivity type second cladding layer provided on the light guide layer,
The multi-quantum structure is characterized in that a barrier configured to have a uniform thickness at the center of the active layer is thicker than a barrier adjacent to the guide layer at the end of the active layer. Well type semiconductor light emitting device. On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
An active layer portion having three or more barriers provided on the first cladding layer;
In the semiconductor light emitting device comprising the second conductivity type second clad layer provided on the active layer portion,
Barrier in the central portion of the active layer section, the energy gap constructed uniformly with each other, which is larger configuration in comparison with the energy gap in the two barrier adjacent to the cladding layer is an end portion of the active layer portion A multiple quantum well semiconductor light emitting device characterized by the above. On the compound semiconductor substrate, at least a first cladding layer of the first conductivity type;
A light guide layer provided on the first cladding layer;
An active layer portion having three or more barriers provided on the light guide layer;
A light guide layer provided on the active layer portion;
In the semiconductor light emitting device comprising the second conductivity type second clad layer provided on the light guide layer,
The energy gap formed uniformly between the barriers in the central portion of the active layer portion is configured to be larger than the energy gap in the barrier adjacent to the guide layer at the end of the active layer portion. A multiple quantum well semiconductor light emitting device.

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