Epitaxial structure of GaN / InGaN quantum well LED with graded In composition well barrier

Abstract

The application discloses an epitaxial structure of a quantum well LED with a gradually changed In component GaN / InGaN quantum well, which comprises, from bottom to top, a substrate, an AlN buffer layer, an N-type GaN layer, a GaN / InGaN superlattice layer, a low-temperature GaN layer, an In component gradually changed GaN / InGaN quantum well layer, an EBL layer and a p-type GaN layer; the In component gradually changed GaN / InGaN quantum well layer comprises n quantum wells and n quantum barriers which are alternately arranged from bottom to top; from the first quantum well to the (n-1)th quantum well, the In component in the quantum well increases gradually; the In component in the nth quantum well is lower than that in the (n-1)th quantum well; when the In component in the xth quantum well exceeds 0.35, the corresponding xth quantum barrier is InGaN material; when the In component in the xth quantum well does not exceed 0.35, the corresponding xth quantum barrier is GaN material; wherein n is a natural number greater than zero, n>=x>0. The above scheme can grow an AlGaInN system LED with high quality and long wavelength, and the InGaN / GaN quantum well structure has high crystal quality.

Description

Technical Field

[0001] This application relates to the field of LEDs with InGaN quantum wells, and more particularly to an epitaxial structure of an LED with a gradient In composition of GaN / InGaN quantum well with a well barrier. Background Technology

[0002] A light-emitting diode (LED) is a semiconductor light-emitting device that directly converts electrical energy into light energy. Currently, most white LEDs are produced by exciting yellow phosphors with blue LEDs to create white light. While this method is widely used, it has certain drawbacks. The phosphors age over time, leading to decreased LED brightness and color temperature drift. Furthermore, the phosphor raw materials require rare earth elements, which are strategic resources. White light produced by exciting yellow phosphors with blue LEDs is of low quality, containing a higher proportion of blue light with a shorter wavelength, which can be harmful to the human eye. Using LEDs of different colors to directly excite and mix to produce white light would not only improve the electro-optical conversion efficiency of the LED device but also mitigate device aging and avoid environmental pollution caused by phosphors.

[0003] Currently, AlGaInN-based LEDs can cover the entire visible light spectrum, but their application is limited to short wavelengths. While the external quantum efficiency (EQ) of GaN-based blue LEDs has reached over 70%, the luminous efficiency drops rapidly in longer wavelength yellow-orange LEDs due to the increased indium (In) content and decreased material quality. Furthermore, with the development of VR technology, existing OLED and LCD display technologies can no longer meet the requirements of rapid response and precise low-light control, leading to the emergence of LED display technology. Currently, red LED lighting uses AlGaInP materials, but severe edge effects limit its application in LED displays. This indicates the enormous development potential of AlGaInN-based long-wavelength LEDs, the prerequisite being the acquisition of high-quality, high-indium-content InGaN materials. As the In content increases, the stress between InGaN and GaN increases, leading to more material defects and a decrease in crystal quality. Additionally, high-In-content InGaN is prone to phase separation at high temperatures, which is another reason limiting the growth of high-quality, high-In-content InGaN. Summary of the Invention

[0004] The purpose of this application is to provide an epitaxial structure for an AlGaInN system LED with a gradient In composition of the well barrier GaN / InGaN quantum well, which can grow high-quality long-wavelength AlGaInN system LEDs. This LED technology has a high crystal quality InGaN / GaN quantum well structure and can be widely used in the field of long-wavelength AlGaInN system LEDs.

[0005] This application discloses an epitaxial structure for an LED with a gradient In composition GaN / InGaN quantum well, comprising, from bottom to top, a substrate, an AlN buffer layer, an N-type GaN layer, a GaN / InGaN superlattice layer, a low-temperature GaN layer, an In composition gradient GaN / InGaN quantum well layer, an EBL layer, and a p-type GaN layer. The In composition gradient GaN / InGaN quantum well layer comprises n quantum wells and n quantum barriers stacked alternately from bottom to top. From the first quantum well to the (n-1)th quantum well, the In composition in the quantum wells increases sequentially. The In composition in the nth quantum well is lower than that in the (n-1)th quantum well. Among the n quantum wells, when the In composition in the xth quantum well exceeds 0.35, the corresponding xth quantum barrier is InGaN material; when the In composition in the xth quantum well does not exceed 0.35, the corresponding xth quantum barrier is GaN material. Wherein, n is a natural number greater than zero, and n ≥ x > 0.

[0006] Optionally, the number of periods in the In composition graded GaN / InGaN quantum well is 5 to 10, where 10 ≥ n ≥ 5.

[0007] Optionally, in the In composition graded GaN / InGaN quantum wells, the thickness of each quantum well from the first quantum well to the (n-1)th quantum well is between 2 and 4 nm, and the thickness of the nth quantum well is less than the thickness of the (n-1)th quantum well; the thickness of each quantum well from the first quantum barrier to the (n-1)th quantum barrier is between 8 and 15 nm, and the thickness of the nth quantum barrier is less than the thickness of the (n-1)th quantum barrier.

[0008] Optionally, when the quantum barrier is an InGaN material, the In composition in the InGaN quantum barrier is 0 to 0.15.

[0009] Optionally, the substrate is formed of one or more materials selected from sapphire, Si, SiC, and ZnO.

[0010] Optionally, the EBL layer is formed of AlGaN material with a thickness of 10–30 nm.

[0011] Optionally, the AlN buffer layer has a thickness of 50–100 nm, the N-type GaN layer has a thickness of 2–3 μm, the GaN / InGaN superlattice layer has 20–30 cycles, each cycle having a GaN thickness of 1–3 nm and an InGaN thickness of 3–5 nm, the low-temperature GaN layer has a thickness of 5–15 nm, and the p-type GaN layer has a thickness of 200–300 nm.

[0012] Optionally, the In composition-gradient GaN / InGaN quantum well has 8 cycles, where n = 8; in the first to the seventh quantum well, the In composition in the quantum well increases from 0.1 to 0.05 to 0.4, and the In composition in the eighth quantum well is 0.3.

[0013] Optionally, the growth temperature of the quantum wells gradually decreases from the first to the seventh quantum well, and the growth temperature of the eighth quantum well is higher than that of the seventh quantum well.

[0014] Optionally, the first quantum well is In 0.1 Ga 0.9 N, with a thickness of 3 nm, and a growth temperature of 800 degrees Celsius; the second quantum well is In. 0.15 Ga 0.85 N, with a thickness of 3 nm, and a growth temperature of 790 degrees Celsius; the third quantum well is In. 0.2 Ga 0.8 N, with a thickness of 3 nm, and a growth temperature of 785 degrees Celsius; the fourth quantum well is In. 0.25 Ga 0.75 N, with a thickness of 3 nm, and a growth temperature of 780 degrees Celsius; the fifth quantum well is In. 0.3 Ga 0.7 N, with a thickness of 3 nm, and a growth temperature of 775 degrees Celsius; the sixth quantum well is In. 0.35 Ga 0.65 N, with a thickness of 3 nm, and a growth temperature of 770 degrees Celsius; the seventh quantum well is In. 0.4 Ga 0.6 N, with a thickness of 3 nm, and a growth temperature of 765 degrees Celsius; the eighth quantum well is In. 0.3 Ga 0.7 The growth temperature was 770°C, with a thickness of 1.5 nm and a growth temperature of 770°C. The reaction chamber pressure of each quantum well was 50–100 Torr. The first to fifth quantum barriers were GaN with a thickness of 13 nm, and the sixth and seventh quantum barriers were In. 0.1 Ga 0.9 The first quantum barrier is N, with a thickness of 13 nm, and the second quantum barrier is GaN, with a thickness of 7 nm.

[0015] This application employs an In-component-gradient GaN / InGaN quantum well structure. In this structure, the In content increases sequentially from bottom to top until reaching the (n-1)th quantum well. This buffers quantum well stress while increasing the device's emission wavelength. The gradual change in In content within the quantum wells alleviates the problem of excessive stress caused by excessively high In content, improves the lattice structure, and enhances internal quantum efficiency. Furthermore, the In content in the nth quantum well is lower than that in the (n-1)th quantum well to alleviate stress between it and the EBL layer. The nth quantum well accounts for a very small proportion of the entire emission well and emits almost no light; therefore, reducing the In content of the nth quantum well does not affect the overall emission wavelength of the device. This approach allows for the growth of high-quality, long-wavelength AlGaInN LEDs. This LED technology features a high-crystal-quality InGaN / GaN quantum well structure and can be widely applied in the field of long-wavelength AlGaInN LEDs. Attached Figure Description

[0016] The accompanying drawings, which form part of the specification, are used to provide a further understanding of the embodiments of this application and illustrate the implementation methods of this application, together with the textual description, to explain the principles of this application. Obviously, the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any creative effort. In the drawings:

[0017] Figure 1 This is a schematic diagram of a quantum well LED epitaxial structure with a gradient In composition of GaN / InGaN in this application;

[0018] Figure 2 This is a schematic diagram of the In composition graded GaN / InGaN quantum well structure of this application.

[0019] The figure shows: 1. Substrate; 2. AlN buffer layer; 3. n-type GaN layer; 4. GaN / InGaN superlattice layer; 5. Low-temperature GaN layer; 6. In composition graded GaN / InGaN quantum well; 7. EBL layer; 8. p-type GaN layer; 101. First quantum well; 102. First quantum barrier; 103. Second quantum well; 104. Second quantum barrier; 105. Third quantum well; 106. Third quantum barrier; 107. Fourth quantum well; 108. Fourth quantum barrier; 109. Fifth quantum well; 110. Fifth quantum barrier; 111. Sixth quantum well; 112. Sixth quantum barrier; 113. Seventh quantum well; 114. Seventh quantum barrier; 115. Eighth quantum well; 116. Eighth quantum barrier. Detailed Implementation

[0020] It should be understood that the terminology, specific structural and functional details used herein are merely for describing particular embodiments and are representative. However, this application may be implemented in many alternative forms and should not be construed as being limited to the embodiments set forth herein.

[0021] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or implying the number of indicated technical features. Therefore, unless otherwise stated, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "multiple" means two or more. The term "comprising" and any variations thereof mean a non-exclusive inclusion, which may include or add one or more other features, integers, steps, operations, units, components, and / or combinations thereof. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] The present application will now be described in detail with reference to the accompanying drawings and optional embodiments.

[0023] Figure 1 This is a schematic diagram of an epitaxial structure of a quantum well LED with a gradient In composition in the well barrier, as described in this application. Figure 1 As shown, the LED epitaxial structure with In composition gradient GaN / InGaN quantum well includes, from bottom to top, a substrate 1, an AlN buffer layer 2, an N-type GaN layer 3, a GaN / InGaN superlattice layer 4, a low-temperature GaN layer 5, an In composition gradient GaN / InGaN quantum well layer 6, an EBL layer 7, and a p-type GaN layer 8.

[0024] The In-component graded GaN / InGaN quantum well layer comprises n quantum wells and n quantum barriers stacked alternately from bottom to top. From the first quantum well to the (n-1)th quantum well, the In component in the quantum wells increases sequentially, with the In component in the nth quantum well being lower than that in the (n-1)th quantum well. Among the n quantum wells, when the In component in the xth quantum well exceeds 0.35, the corresponding xth quantum barrier is made of InGaN material; when the In component in the xth quantum well does not exceed 0.35, the corresponding xth quantum barrier is made of GaN material. Here, n is a natural number greater than zero, and n ≥ x > 0.

[0025] This application employs an In-component-gradient GaN / InGaN quantum well structure. In this structure, the In content increases sequentially from bottom to top until reaching the (n-1)th quantum well. This buffers quantum well stress while increasing the device's emission wavelength. The gradual change in In content within the quantum wells alleviates the problem of excessive stress caused by excessively high In content, improves the lattice structure, and enhances internal quantum efficiency. Furthermore, the In content in the nth quantum well is lower than that in the (n-1)th quantum well to alleviate stress between it and the EBL layer. The nth quantum well accounts for a very small proportion of the entire emission well and emits almost no light; therefore, reducing the In content of the nth quantum well does not affect the overall emission wavelength of the device. This approach allows for the growth of high-quality, long-wavelength AlGaInN LEDs. This LED technology features a high-crystal-quality InGaN / GaN quantum well structure and can be widely applied in the field of long-wavelength AlGaInN LEDs.

[0026] It is important to understand that the In content in the quantum wells increases sequentially until it reaches the penultimate quantum well from the bottom, and the In content in the penultimate quantum well is lower than that in the penultimate quantum well. Correspondingly, in the aforementioned In-component graded GaN / InGaN quantum wells, when the In content of the InGaN quantum well does not exceed 0.35, the quantum barrier is GaN material; when the In content of the InGaN quantum well exceeds 0.35, the quantum barrier is InGaN material. When the quantum barrier is InGaN material, the In content in the InGaN quantum barrier is 0–0.15.

[0027] Specifically, the number of periods of the In-component graded GaN / InGaN quantum well is 5 to 10, that is, 10 ≥ n ≥ 5. The number of periods of the quantum well refers to the period of alternating stacking of quantum wells and quantum barriers. When n equals 5, the number of periods of the In-component graded GaN / InGaN quantum well is 5. When n equals 10, the number of periods of the In-component graded GaN / InGaN quantum well is 10.

[0028] Specifically, the substrate is formed of one or more materials selected from sapphire, Si, SiC, and ZnO.

[0029] Specifically, in the In composition graded GaN / InGaN quantum wells, the thickness of each quantum well from the first to the (n-1)th quantum well is between 2-4 nm, with the thickness of the nth quantum well being less than that of the (n-1)th quantum well; the thickness of each quantum well from the first to the (n-1)th quantum barrier is between 8-15 nm, with the thickness of the nth quantum barrier being less than that of the (n-1)th quantum barrier. The nth quantum well and the nth quantum barrier are terminal quantum wells, which have poorer quality during formation and do not require a larger thickness; therefore, the thickness of the nth quantum well is less than that of the (n-1)th quantum well, and the thickness of the nth quantum barrier is less than that of the (n-1)th quantum barrier.

[0030] Specifically, the EBL layer 7 is formed of AlGaN material with a thickness of 10–30 nm.

[0031] Specifically, the AlN buffer layer 2 has a thickness of 50–100 nm, the N-type GaN layer 3 has a thickness of 2–3 μm, the GaN / InGaN superlattice layer 4 has 20–30 cycles, each cycle having a GaN thickness of 1–3 nm and an InGaN thickness of 3–5 nm, the low-temperature GaN layer 5 has a thickness of 5–15 nm, and the p-type GaN layer 8 has a thickness of 200–300 nm.

[0032] Figure 2 This is a schematic diagram of the In composition graded GaN / InGaN quantum well structure of this application, as shown below. Figure 2 As shown, this embodiment uses an In composition graded GaN / InGaN quantum well with 8 periods, where n = 8, as an example for illustration.

[0033] In the first to the seventh quantum wells (101, 103, 105, 107, 109, 111, 113), the In content in the quantum wells increases sequentially from 0.1 to 0.4, starting from 0.05. The In content of the eighth quantum well 115 is less than that of the seventh quantum well 113, and the In content of the eighth quantum well 115 can be 0.3.

[0034] This application employs an In-component-gradient GaN / InGaN quantum well structure. In the In-component-gradient GaN / InGaN quantum well, the In component in the quantum well increases sequentially from bottom to top until it reaches the seventh quantum well. This can buffer the stress of the quantum well while increasing the emission wavelength of the device. The gradual change in the In component in the quantum well gradually alleviates the problem of excessive stress caused by excessive In component in the quantum well, improves the lattice, and increases the internal quantum efficiency.

[0035] In the sixth quantum well 111 and the seventh quantum well 113, the In content is relatively high (over 0.35%), making them the main light-emitting wells. The quantum barrier material, InGaN, has a lower bandgap than GaN, resulting in weaker confinement of charge carriers, further increasing the luminous efficiency of the sixth and seventh quantum wells 111 and 113. Furthermore, the In content in the eighth quantum well 115 is lower than that in the seventh quantum well 113 to alleviate stress between it and the EBL layer. The eighth quantum well 115 accounts for a very small proportion of the entire light-emitting well and emits almost no light; therefore, reducing the In content of the eighth quantum well 115 does not affect the overall emission wavelength of the device. This method allows for the growth of high-quality, long-wavelength AlGaInN LEDs. This LED technology features a high-quality InGaN / GaN quantum well structure and can be widely applied in the field of long-wavelength AlGaInN LEDs.

[0036] It is important to understand that in In-component graded GaN / InGaN quantum wells, the In component refers to the proportion of In in the InGaN quantum well, or in atomic proportions. In this embodiment, the ratio of In to Ga and Ga to N is 1:1. As the In component gradually increases from the first to the seventh quantum well, the Ga component gradually decreases from the first to the seventh quantum well.

[0037] Specifically, in the first to seventh quantum wells, the growth temperature of the quantum wells gradually decreases, while the growth temperature of the eighth quantum well is higher than that of the seventh quantum well. In this embodiment, the In content of the first to seventh quantum wells gradually increases. Correspondingly, the decrease in growth temperature is beneficial to increasing the incorporation of In during the growth process, thereby causing the In content to gradually increase.

[0038] The following describes a method for fabricating an In-composed graded GaN / InGaN quantum well structure, including the following steps: Eight In-composed graded GaN / InGaN quantum wells are fabricated on a silicon substrate using MOCVD. The processes preceding the quantum wells are performed according to normal LED growth processes. In the quantum well process, the first quantum well is In-composed... 0.1 Ga 0.9 N, with a thickness of 3nm; then, the In content is increased sequentially in each quantum well until the In content in the sixth and seventh quantum wells reaches the required band gap for the emission wavelength of InGaN; finally, when growing the eighth quantum well, the In content in the quantum well should be appropriately reduced to release some stress and to a certain extent improve the lattice damage caused by the excessive In content in the previous quantum wells.

[0039] Taking an LED with an In-component graded GaN / InGaN quantum well structure and an emission wavelength of 600nm as an example, an eight-cycle In-component graded GaN / InGaN quantum well is fabricated on a silicon substrate using MOCVD. The processes preceding the quantum wells are performed according to normal LED growth processes. In the quantum well process, the first quantum well 101 is In... 0.1 Ga 0.9 The N-type quantum well has a thickness of 3 nm, a growth temperature of 800 degrees Celsius, and a reaction chamber pressure of 50–100 Torr; the second quantum well 103 is In. 0.15 Ga 0.85 N, with a thickness of 3 nm, growth temperature of 790 degrees Celsius, and reaction chamber pressure of 50–100 Torr; the third quantum well 105 is In. 0.2 Ga 0.8 N, with a thickness of 3 nm, growth temperature of 785 degrees Celsius, and reaction chamber pressure of 50–100 Torr; the fourth quantum well 107 is In. 0.25 Ga 0.75 N, with a thickness of 3 nm, growth temperature of 780 degrees Celsius, and reaction chamber pressure of 50–100 Torr; the fifth quantum well 109 is In. 0.3 Ga 0.7 N, with a thickness of 3 nm, growth temperature of 775 degrees Celsius, and reaction chamber pressure of 50–100 Torr; the sixth quantum well 111 is In. 0.35 Ga 0.65 N, with a thickness of 3 nm, growth temperature of 770 degrees Celsius, and reaction chamber pressure of 50–100 Torr; the seventh quantum well 113 is In. 0.4 Ga 0.6 N, with a thickness of 3 nm, growth temperature of 765 degrees Celsius, and reaction chamber pressure of 50–100 Torr; the eighth quantum well 115 is In. 0.3 Ga 0.7 The first quantum barrier (102, 104, 106, 108, 110) is GaN, with a thickness of 13 nm, grown at 770°C, and with a reaction chamber pressure of 50–100 Torr. The second quantum barrier (112) and the third quantum barrier (114) are In. 0.1 Ga 0.9The first quantum barrier, N, was 13 nm thick and grown at 800 °C under a reaction chamber pressure of 50 Torr. The second quantum barrier, 116, was GaN, 7 nm thick, grown at 850 °C under a reaction chamber pressure of 50–100 Torr. A 30 nm EBL layer was then grown using Al0.2Ga0.8N at 1050 °C, followed by p-type GaN at 1000 °C.

[0040] It should be noted that the inventive concept of this application can form many embodiments, but due to the limited space of the application documents, they cannot all be listed. Therefore, without conflict, the embodiments described above or the technical features can be arbitrarily combined to form new embodiments. After the embodiments or technical features are combined, the original technical effect will be enhanced.

[0041] The above description, in conjunction with specific optional embodiments, provides a further detailed explanation of this application and should not be construed as limiting the specific implementation of this application to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of this application, and all such modifications or substitutions should be considered within the scope of protection of this application.

Claims

1. A quantum well LED epitaxial structure with In composition graded GaN / InGaN, characterized in that, It includes, from bottom to top, a substrate, an AlN buffer layer, an N-type GaN layer, a GaN / InGaN superlattice layer, a low-temperature GaN layer, an In composition graded GaN / InGaN quantum well layer, an EBL layer, and a p-type GaN layer; The In composition graded GaN / InGaN quantum well layer comprises n quantum wells and n quantum barriers that are alternately stacked from bottom to top. From the first quantum well at the bottom to the (n-1)th quantum well, the In component in the quantum well increases sequentially. The In component in the nth quantum well is lower than the In component in the (n-1)th quantum well; In a set of n quantum wells, when the In content of the x-th quantum well exceeds 0.35, the corresponding x-th quantum barrier is made of InGaN material; when the In content of the x-th quantum well does not exceed 0.35, the corresponding x-th quantum barrier is made of GaN material; where n is a natural number greater than zero, and n≥x>0.

2. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 1, characterized in that, The In composition graded GaN / InGaN quantum well has a period number of 5 to 10, where 10 ≥ n ≥ 5.

3. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 1, characterized in that, In the In composition graded GaN / InGaN quantum wells, the thickness of each quantum well from the first quantum well to the (n-1)th quantum well is between 2 and 4 nm, and the thickness of the nth quantum well is less than the thickness of the (n-1)th quantum well; the thickness of each quantum well from the first quantum barrier to the (n-1)th quantum barrier is between 8 and 15 nm, and the thickness of the nth quantum barrier is less than the thickness of the (n-1)th quantum barrier.

4. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 1, characterized in that, When the quantum barrier is made of InGaN material, the In composition of the InGaN quantum barrier is 0 to 0.

15.

5. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 1, characterized in that, The substrate is formed of one or more materials selected from sapphire, Si, SiC, and ZnO.

6. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 1, characterized in that, The EBL layer is formed of AlGaN material and has a thickness of 10–30 nm.

7. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 6, characterized in that, The AlN buffer layer has a thickness of 50–100 nm, the N-type GaN layer has a thickness of 2–3 μm, the GaN / InGaN superlattice layer has 20–30 cycles, each cycle having a GaN thickness of 1–3 nm and an InGaN thickness of 3–5 nm, the low-temperature GaN layer has a thickness of 5–15 nm, and the p-type GaN layer has a thickness of 200–300 nm.

8. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 1, characterized in that, The In composition graded GaN / InGaN quantum well has a period number of 8, where n = 8; In the first to the seventh quantum wells, the In content in the quantum wells increases sequentially from 0.1 to 0.05 to 0.4, and the In content in the eighth quantum well is 0.

3.

9. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 8, characterized in that, In the first to the seventh quantum well, the growth temperature of the quantum well gradually decreases, and the growth temperature of the eighth quantum well is higher than that of the seventh quantum well.

10. The quantum well LED epitaxial structure with In composition gradient GaN / InGaN as described in claim 9, characterized in that, The first quantum well is In 0.1 Ga 0.9 N, with a thickness of 3 nm, and a growth temperature of 800 degrees Celsius; the second quantum well is In. 0.15 Ga 0.85 N, with a thickness of 3 nm, and a growth temperature of 790 degrees Celsius; the third quantum well is In. 0.2 Ga 0.8 N, with a thickness of 3 nm, and a growth temperature of 785 degrees Celsius; the fourth quantum well is In. 0.25 Ga 0.75 N, with a thickness of 3 nm, and a growth temperature of 780 degrees Celsius; the fifth quantum well is In. 0.3 Ga 0.7 N, with a thickness of 3 nm, and a growth temperature of 775 degrees Celsius; the sixth quantum well is In. 0.35 Ga 0.65 N, with a thickness of 3nm, and a growth temperature of 770 degrees Celsius; The seventh quantum well is In 0.4 Ga 0.6 N, with a thickness of 3 nm, and a growth temperature of 765 degrees Celsius; the eighth quantum well is In. 0.3 Ga 0.7 The growth temperature was 770°C, with a thickness of 1.5 nm and a growth temperature of 770°C. The reaction chamber pressure of each quantum well was 50–100 Torr. The first to fifth quantum barriers were GaN with a thickness of 13 nm, and the sixth and seventh quantum barriers were In. 0.1 Ga 0.9 The first quantum barrier is N, with a thickness of 13 nm, and the second quantum barrier is GaN, with a thickness of 7 nm.

Images