III-V group compound multi-junction solar cell

Abstract

The utility model provides an III-V group compound multi-junction solar cell. The III-V group compound multi-junction solar cell sequentially comprises a back metal layer and a sub-cell from a backlight side to a light incident side, the solar cell comprises a front metal electrode pattern layer, a multi-quantum well structure, an antireflection film and a front metal electrode pattern layer, the multi-quantum well structure is arranged to be capable of absorbing sunlight and emitting visible light band specific wavelength light, so that the surface of the whole cell presents a color corresponding to the specific wavelength, and the problem of chromatic aberration caused by inconsistent light reflection on the surface of a traditional cell is solved; and the target specific wavelength can be obtained by adjusting the multi-quantum well structure, so that different apparent colors of the battery piece can be obtained. Meanwhile, the multi-quantum well structure has a current expansion effect, so that the total area of the grid lines is allowed to be reduced, the light absorption of the grid lines is reduced, and the cell efficiency is improved under the condition that the current collection effect is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a III-V compound multi-junction solar cell structure. Background Art

[0002] Solar cells are a clean and environmentally friendly energy source, among which multi-junction solar cells based on III-V compounds are currently the most common high-efficiency solar cells.

[0003] An anti-reflection film ACR is usually set on the top of the above-mentioned multi-junction battery near the light incident side. It uses the principle of light interference to make the reflected light waves of the incident light interfere with the reflected light waves inside the film, reduce the reflectivity, reduce reflection losses, and allow more light to enter the battery, be absorbed and converted into electrical energy, thereby improving the utilization rate of light.

[0004] The apparent color of the cell is determined by the reflected light of the multi-junction cell mentioned above. The multi-junction solar cells currently on the market have different reflectivities in the visible light band on the surfaces of different cells due to differences in the thickness of the top cell epitaxial layer generated during the process and differences in the thickness of the anti-reflection film ARC set on the top of the cell. As a result, there are obvious color differences on the surfaces of different cells, affecting the consistency of the cell products. Utility Model Content

[0005] In view of this, the utility model provides a III-V compound solar cell structure, which can reduce the color difference of different solar cell surfaces in the visible light band on the one hand, and improve the cell conversion efficiency on the other hand.

[0006] The utility model provides a III-V compound multi-junction solar cell.

[0007] It has a light-entering side and a backlight side, and includes, from the backlight side to the light-entering side, a back metal layer, at least one sub-cell; a multi-quantum well structure, an anti-reflection film, and a front metal electrode pattern layer. The metal of the pattern layer is directly connected to the multi-quantum well structure through a contact layer. The back metal layer replaces the substrate as a supporting base for the cell and also serves as an electrode layer. The multi-quantum well structure can absorb sunlight and emit light of a specific wavelength in the visible light band.

[0008] According to some embodiments, the multi-quantum well structure can obtain target specific wavelength light in the visible light band by adjusting material composition and thickness. The multi-quantum well structure absorbs sunlight with a wavelength smaller than the target specific wavelength and emits target specific wavelength light.

[0009] According to some embodiments, the front metal electrode pattern layer is a grid line structure, and the grid line area accounts for less than 5% of the battery surface area, preferably less than 4%, and more preferably less than 3%.

[0010] According to some embodiments, a tunnel junction is provided between epitaxial layers of each sub-cell in the at least one sub-cell.

[0011] According to some embodiments, each sub-cell layer includes a window layer, a sub-cell PN junction N region, a sub-cell PN junction P region, and a sub-cell back field layer, wherein the PN junction material is selected from GaInP, AlGaInP, GaAs, InGaAs, InGaAsP, the window layer material is selected from AlInP, GaInP, InAlGaAs, and the back field layer material is selected from AlGaAs and GaInP.

[0012] According to some embodiments, the multi-quantum well structure includes a confinement layer, a well layer, and a barrier layer, and the well layer and the barrier layer are alternately stacked in a periodic arrangement, and the periodic arrangement structure is arranged between the confinement layers. The barrier layer and the well layer of the multi-quantum well structure have an overlapping cycle number greater than 5, preferably greater than 10.

[0013] According to some embodiments, the thickness of each single layer of the barrier layer of the multi-quantum well structure is preferably 5nm-30nm, and the thickness of each single layer of the well layer is preferably 3nm-10nm;

[0014] According to some embodiments, the confinement layer material of the multi-quantum well structure can be selected to be lattice-matched with GaAs (Al x Ga 1-x ) 0.5 In 0.5 For P materials, x ranges from 0.56 to 1.

[0015] According to some embodiments, the well layer material of the multi-quantum well structure is (Al x Ga 1-x ) 0.5 In 0.5 For P material, the range of x is 0-0.56.

[0016] According to some embodiments, the barrier layer material of the multi-quantum well structure is selected from AlInP or (Al x Ga 1-x ) 0.5 In 0.5 For P materials, x ranges from 0.56 to 1.

[0017] According to some embodiments, the multi-quantum well structure adopts a relatively low n-type doping concentration of 1x10 17 cm -3 Up to 1x10 18 cm -3 .

[0018] According to some embodiments, the ohmic contact layer may be selected from GaAs, GaInP, and AlInP.

[0019] According to some embodiments, the anti-reflection film includes SiO2, Si3N4, TiO2, Al2O3, Ta2O3, Nb2O3, ZnS, MgF2 and combinations thereof.

[0020] The utility model arranges a multi-quantum well structure above the top cell of the multi-junction cell close to the light incident side. The multi-quantum well structure can absorb sunlight and emit light of a specific wavelength in the visible light band, so that the cell surface presents the color corresponding to the above-mentioned specific wavelength light, thereby solving the color difference problem of the cell piece.

[0021] At the same time, since the multi-quantum well structure can obtain different emission wavelengths by adjusting the material composition and thickness, the utility model can perform the above adjustment to obtain target specific wavelength light in the visible light band, that is, the multi-quantum well structure absorbs sunlight smaller than the above target specific wavelength and emits target specific wavelength light.

[0022] Furthermore, the added multi-quantum well structure has an expansion effect on the current. While ensuring the current collection effect, it allows the electrode metal grid line width to be reduced or the spacing to be increased, reducing the total grid line area, reducing the grid line's absorption of light, and further improving battery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of a III-V compound multi-junction solar cell according to an embodiment of the utility model;

[0024] Figure 2 This is a schematic diagram of the structure of a GaAs triple-junction solar cell according to another embodiment of the utility model;

[0025] Reference numerals list

[0026] 1. Front metal electrode pattern layer, 2. Contact layer, 3. Anti-reflection film, 4. Multiple quantum well structure, 41 / 44. Confinement layer, 42. Barrier layer, 43. Well layer, 5. Sub-cell layer, 51. GaInP junction sub-cell layer, 52. GaAs junction sub-cell layer, 53. InGaAs junction sub-cell layer, 6. Tunneling junction layer, 61. First tunneling junction layer, 62. Second tunneling junction layer, 7. The nth sub-cell layer, 8. Back metal layer. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the present invention.

[0028] Figure 1This is a schematic diagram of the structure of a III-V compound multi-junction solar cell. As shown in the figure, from the backlight side to the light-incident side, it includes: a back metal layer 8, at least one sub-cell 5, 7; a multi-quantum well structure 4 arranged on the top of the sub-cell, an anti-reflection film 3, and a front metal electrode pattern layer 1. The metal of the pattern layer 1 is directly connected to the multi-quantum well structure through a contact layer. The back metal layer replaces the substrate as the supporting base of the cell and also serves as an electrode layer. The multi-quantum well structure can absorb sunlight and emit light of a specific wavelength in the visible light band.

[0029] Sunlight irradiates the cell along the light-entering side, and the multi-quantum well structure absorbs some photons whose photon energy is greater than the band gap of the well layer material in the multi-quantum well structure, and at the same time emits light of a specific wavelength in the visible light band in all directions. Since the intensity of the above-mentioned wavelength light is higher than the reflected light after the anti-reflection film and the cell absorption, the surface of the cell presents the color of the light of a specific wavelength, and eventually the colors of the surfaces of different cell cells tend to be consistent; at the same time, the light of a specific wavelength emitted toward the cell will be absorbed by the cell sub-cell and become light that can be converted into electricity by the cell.

[0030] The multi-quantum well design of the utility model can solve the problem of apparent color difference of the battery cell and ensure the consistency of the appearance quality of the battery cell.

[0031] According to some embodiments, the multi-quantum well structure can obtain target specific wavelength light in the visible light band by adjusting material composition and thickness. The multi-quantum well structure absorbs sunlight with a wavelength smaller than the target specific wavelength and emits target specific wavelength light.

[0032] The above-mentioned target specific wavelength light reflects the surface color of the battery cell, and different apparent colors of the battery cell can be obtained by adjustment.

[0033] According to some embodiments, the main functions of the front metal electrode pattern layer 1 and the back metal layer 8 are to collect the current generated by the battery cell; in order to reduce the impact on the amount of incident light, the above metals can be selected as one or more of silver, gold, nickel, copper, and aluminum. It is known in the art that the above materials are not limited as long as they can collect current.

[0034] Furthermore, the front metal electrode pattern layer 1 is distributed in a grid shape; usually, the grid arrangement area accounts for 5% to 8% of the surface area of ​​the solar cell.

[0035] The above-mentioned multi-quantum well structure reduces the above-mentioned proportion to less than 5%, preferably less than 4%, and more preferably less than 3% while ensuring the current collection effect. Specifically, since the above-mentioned multi-quantum well structure acts as a current expansion layer on the top of the battery, the current collection efficiency of the metal grid line is improved, and the width of the surface grid line of the utility model can be reduced or the gap between the grid lines can be increased, thereby reducing the total area of ​​the grid line. Compared with the conventional 5% to 8%, the utility model reduces the absorption of incident light by the metal grid line and improves the battery efficiency.

[0036] Specifically, the surface metal grid lines usually occupy 5%-8% of the surface area of ​​the cell, which prevents sunlight from entering the area covered by the metal grid lines to generate photocurrent. Reducing the metal grid line area on the surface of the cell can effectively increase the current of the cell. Among them, the spacing between the metal grid lines is mainly limited by the lateral conductivity of the material layer on the surface of the cell. The added multi-quantum well structure provides a lateral current expansion layer with a thickness of about 500nm to 1000nm above each sub-cell structure, which enhances the lateral conductivity of the cell surface and improves the current collection efficiency of the surface metal grid lines. Therefore, in the design of the cell structure, the width of the metal grid lines on the surface of the cell can be reduced to achieve the same current collection effect as the grid lines of conventional solar cells, reduce the total area of ​​the grid lines, and reduce the light absorption of the grid lines, so that more light is absorbed by the cell, thereby improving the cell efficiency.

[0037] According to some embodiments, the at least one sub-cell may be selected as a multiple sub-cell structure, for example, two, three, or four sub-cells, and tunnel junctions are provided between epitaxial layers of each sub-cell.

[0038] Each sub-cell absorbs light in a different wavelength range. In order to maximize the use of incident light, the sub-cells of the multi-junction cell structure are arranged in a manner that the band gap gradually decreases along the light incident direction.

[0039] Each of the sub-cell layers includes a sub-cell window layer, a sub-cell PN junction N region, a sub-cell PN junction P region, and a sub-cell back field layer. The main function of the sub-cell window layer and the back field layer is to limit the movement of photogenerated carriers and increase the utilization rate of photons. Therefore, the bandgap widths of the sub-cell window layer and the back field layer need to be larger than the bandgap widths of the sub-cell PN junction N region and P region materials, respectively.

[0040] The first subcell layer, i.e. the top cell, is close to the light incident side and has the largest band gap. The absorption layer material is preferably a wide bandgap direct bandgap material such as GaInP and AlGaInP. At this time, the window layer can be made of AlInP material, and the back field layer can be made of AlGaInP material.

[0041] The second to nth sub-cell layers are located in the middle and bottom of the multiple sub-cell layers of the solar cell, and their band gaps gradually decrease; the absorption layer material is preferably GaAs, InGaAs, InGaAsP and other materials, at this time, the window layer can be selected from AlInP, GaInP, InAlGaAs and other materials, and the back field layer can be selected from AlGaAs, GaInP and other materials.

[0042] The tunneling junction layer is composed of p++ / n++ tunnel diodes, which are used for low-resistance electrical connection of subcells in multi-junction solar cells; the highly doped PN junction can increase the tunneling probability, and the doping concentration of the n-type material is preferably 1x10 18 cm -3 Up to 5x10 19 cm -3 The p-type material doping concentration is preferably 5x10 18 cm -3 Up to 4x10 20 cm -3 The n-type and p-type materials can be selected from GaAs, AlGaAs, GaInP and other materials. The n-type doping can be selected from Si, Te, Se and other doping, and the p-type material can be selected from Zn, C and other doping.

[0043] According to some embodiments, the contact layer may be composed of an n-type III-V semiconductor compound material that matches the epitaxial substrate, such as GaAs, GaInP, AlInP and the like.

[0044] The contact layer is arranged between the metal electrode and the epitaxial material, so that the battery and the metal are electrically connected with low resistance. When the top battery selects GaInP, AlGaInP and other materials as the absorption layer, GaAs material is preferably used as the contact layer; the doping concentration of the n-type material is 1x10 18 cm -3 Up to 1x10 19 cm -3 .

[0045] According to some embodiments, the anti-reflection film is composed of one or more dielectric layers, and commonly used materials include SiO2, Si3N4, TiO2, Al2O3, Ta2O3, Nb2O3, ZnS, MgF2, etc. For example, two dielectric layers with different refractive indices can be selected to prepare Al2O3 with a thickness of 70nm and TiO2 with a thickness of 40nm to obtain an Al2O3 / TiO2 double-layer anti-reflection film with an overall reflectivity of approximately 10%. Those skilled in the art know that the anti-reflection film is not limited to the above-mentioned combination and materials.

[0046] According to some embodiments, the multi-quantum well structure is composed of three parts: a confinement layer, a well layer, and a barrier layer;

[0047] The multi-quantum well structure is a structure with multiple potential wells formed by alternately growing potential barriers and potential wells in multiple single quantum well structures. The bandgap width of the barrier layer in the multi-quantum well is relatively large, and the bandgap width of the potential well layer is relatively small. When in equilibrium, electrons and holes are confined in each potential well, and photons are emitted when electrons and holes undergo radiation recombination. The limiting layer is a material with a larger bandgap width on both sides of the multi-quantum well structure, and its function is to limit the overflow of carriers from the multi-quantum well structure.

[0048] Furthermore, the confinement layer material of the multi-quantum well structure can be selected from AlInP or (Al x Ga 1-x ) 0.5 In 0.5 P material, the range of x is preferably 0.56 to 1, within this range (Al x Ga 1-x ) 0.5 In 0.5 P is an indirect bandgap material to reduce the absorption of photons. The bandgap width of the restriction layer material needs to be greater than that of the well layer material to improve the quantum efficiency of the quantum well. The thickness of the restriction layer material is preferably greater than 50 nm.

[0049] Furthermore, the well layer material of the multi-quantum well structure is lattice-matched with the epitaxial substrate (Al x Ga 1-x ) 0.5 In 0.5 P material, the range of x can be selected from 0 to 0.56. x Ga 1-x ) 0.5 In 0.5 P is a direct bandgap material that can efficiently utilize photons. The thickness of the well layer is preferably greater than 3 nm and less than 10 nm.

[0050] Furthermore, the barrier layer material of the multi-quantum well structure can be selected from AlInP or (Al x Ga 1-x ) 0.5 In 0.5 P material, the range of x is preferably 0.56 to 1, within this range (Al x Ga 1-x ) 0.5 In 0.5 P is an indirect bandgap material, which reduces the absorption of photons and has a larger bandgap width than the well layer material; its thickness is preferably selected to be greater than 5 nm and less than 30 nm.

[0051] Furthermore, the multi-quantum well structures all use low N-type doping, and the n-type doping can be Si or other doping, with a doping concentration of 1x1017 cm -3 Up to 1x10 18 cm -3 ;

[0052] In the above quantum well structure, the multi-quantum well (Al x Ga 1-x ) 0.5 In 0.5 The composition of the P material and the thickness and number of quantum wells adjust the specific wavelength of light it emits, thereby modulating the visible color of the final cell.

[0053] In the embodiment of the present application, the design of the quantum well structure can solve the problem of color difference between different battery cells, ensure the consistency of the appearance quality of the battery cells, and at the same time, improve the battery conversion efficiency.

[0054] Figure 2 is a structural diagram of a specific application scenario of the above embodiment, specifically a schematic diagram of the structure of a GaAs triple-junction solar cell;

[0055] The order from the backlight side to the light incident side includes:

[0056] The sequence from the backlight side to the light-incoming side includes: a back metal layer 8, at least one subcell 5; a multi-quantum well structure 4, an anti-reflection film 3, and a front metal electrode pattern layer 1, wherein the metal of the pattern layer 1 is directly connected to the multi-quantum well structure 4 through the contact layer 2, and the back metal layer 8 replaces the substrate as the supporting base of the battery and also serves as an electrode layer, wherein the multi-quantum well structure 4 can absorb sunlight and emit light of a specific wavelength in the visible light band. The multi-quantum well structure includes a confinement layer 41 / 44, and a barrier layer 42 and a well layer 43 arranged between the confinement layers, wherein the barrier layer 42 and the well layer 43 are periodically arranged in an alternating superposition manner.

[0057] The specific preparation process is:

[0058] 1. After growing AlAs peeling layer and n-type GaAs contact layer on N-type GaAs substrate; multiple quantum well structure, GaInP junction cell, first tunnel junction, GaAs junction cell, second tunnel junction, InGsAs junction cell.

[0059] Specifically, the front and rear confinement layers of the multi-quantum well structure are made of AlInP material that matches the epitaxial substrate lattice, and the thickness is 200nm. The well layer of the multi-quantum well structure is made of GaInP material that matches the epitaxial substrate lattice, and the thickness is 4-6nm. The barrier layer of the multi-quantum well structure is made of (Al 0.7 Ga 0.3 ) 0.5 In 0.5P material, with a thickness of 8-10nm, the number of well layers and barrier layers in the multi-quantum well structure is 15, and Si is selected as the n-type dopant in the multi-quantum well structure material, with a doping concentration of 5x10 17 cm -3 The multi-quantum well structure absorbs photons with wavelengths less than 630nm and emits photons with a wavelength of 630nm. By changing the number of multi-quantum well cycles in the multi-quantum well structure, the intensity of the emission wavelength, that is, the color depth of the cell, can be adjusted.

[0060] The window layer of GaInP and GaAs junction cells uses AlInP material, the back field layer uses AlGaInP and AlGaAs materials respectively, the first and second tunnel junctions both use AlGaAs p++ / AlGaAs n++ structure, and a multi-layer AlInGaAs layer with a gradient composition is used in front of the InGsAs junction cell to improve the growth quality of InGaAs material. The window layer of the InGaAs junction cell uses InAlGaAs material, and the back field uses GaInP material; finally, InAlGaAs material is grown as the p-type contact layer.

[0061] 2. Prepare a P-side metal layer of copper or nickel alloy on the surface of the epitaxial wafer by evaporation as the back electrode.

[0062] 3. Use a selective etching solution to corrode the AlAs peeling layer so that the battery structure is peeled off from the substrate.

[0063] 4. Prepare N metal pattern electrodes and gate lines on the GaAs contact layer. The metal pattern accounts for 3%-5% of the battery surface area, and 3% is preferred in this embodiment.

[0064] 5. Remove the GaAs contact layer in the non-metallic area and prepare an anti-reflection film in the non-metallic area.

[0065] The final result is a cell that appears red, corresponding to a wavelength of about 630nm.

[0066] In another embodiment, another multi-quantum well structure is provided, in which the front and rear confinement layers are made of AlInP material that matches the epitaxial substrate lattice, and the thickness is 200nm, and the well layer of the multi-quantum well structure is made of AlInP material that matches the epitaxial substrate lattice. 0.3 Ga 0.7 ) 0.5 In 0.5 P material, with a thickness of 8-10nm, and the barrier layer of the multi-quantum well structure is selected to match the lattice of the epitaxial substrate (Al 0.7 Ga 0.3 ) 0.5 In 0.5P material, thickness of 28-30nm, the number of well layers of the multi-quantum well structure is 15; the multi-quantum well structure absorbs photons with wavelengths less than 590nm and emits photons with a wavelength of 590nm. Under this material structure, the emission wavelength can be changed by changing the thickness of the barrier layer of the multi-quantum well structure. Specifically, by changing the thickness of the inner well layer of the multi-quantum well structure to 3-4nm, it is possible to absorb photons with wavelengths less than 570nm and emit photons with a wavelength of 570nm. Prepared by the same process as above and adjusting the multi-quantum well, the color of the cell can be obtained, which is yellow-green or yellow in appearance, corresponding to the visible wavelength of about 570-590nm.

[0067] It can be seen that by adding a multi-quantum well layer structure and setting the thickness and composition of the well layer material in the multi-quantum well layer, the cell emits 630nm and 570-590nm light upward, forming a red or yellow-based color on the surface of the cell, reducing the color difference between different epitaxial wafers. At the same time, the multi-quantum well structure has the function of expanding the current at the top of the cell, improving the current collection efficiency of the metal grid line, thereby reducing the grid line's proportion of the cell surface area, reducing the grid line's absorption of light, and improving the cell efficiency.

[0068] The above is a specific implementation of the embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A III-V compound multi-junction solar cell, It has a light incident side and a backlight side, and the sequence from the backlight side to the light incident side includes: a back metal layer, at least one subcell; A multi-quantum well structure, an anti-reflection film, and a front metal electrode pattern layer, wherein the metal of the pattern layer is directly connected to the multi-quantum well structure through a contact layer, and the back metal layer replaces the substrate as a supporting base for the battery and also serves as an electrode layer, wherein the multi-quantum well structure can absorb sunlight and emit light of a specific wavelength in the visible light band.

2. The multi-junction solar cell according to claim 1, wherein the multi-quantum well structure can obtain target specific wavelength light in the visible light band by adjusting material composition and thickness, and the multi-quantum well structure absorbs sunlight shorter than the above target specific wavelength and emits target specific wavelength light. 3 . The multi-junction solar cell according to claim 1 , wherein the front metal electrode pattern layer is a grid line structure, and the grid line area accounts for less than 5% of the cell surface area.

4. The multi-junction solar cell as claimed in claim 3, wherein the ratio of the grid line area to the cell surface area is preferably less than 4%. 5 . The multi-junction solar cell according to claim 4 , wherein the ratio of the grid line area to the cell surface area is more preferably less than 3%. 6 . The multi-junction solar cell according to claim 1 , wherein a tunnel junction is provided between epitaxial layers of each sub-cell in the at least one sub-cell.

7. The multi-junction solar cell as described in claim 1, wherein the multi-quantum well structure comprises a confinement layer, a well layer, and a barrier layer, the well layer and the barrier layer are alternately stacked in a periodic arrangement, and the periodic arrangement structure is arranged between the confinement layers, and the barrier layer and the well layer of the multi-quantum well structure have an overlapping cycle number greater than 5. 8 . The multi-junction solar cell according to claim 7 , wherein the barrier layer and well layer overlap cycles of the multi-quantum well structure are preferably greater than 10.

9. The multi-junction solar cell as claimed in claim 7, wherein the thickness of each single layer of the barrier well layer of the multi-quantum well structure is preferably 3nm-30nm.

10. The multi-junction solar cell according to claim 1, wherein the multi-quantum well structure comprises a confinement layer, a well layer, and a barrier layer, wherein the well layer and the barrier layer are alternately stacked in a periodic arrangement, and the periodic arrangement structure is arranged between the confinement layers, and the confinement layer material of the multi-quantum well structure is selected to be lattice-matched with the epitaxial substrate (Al x Ga 1-x ) 0.5 In 0.5 For P materials, x ranges from 0.56 to 1.

11. The multi-junction solar cell according to claim 1, wherein the multi-quantum well structure comprises a confinement layer, a well layer, and a barrier layer, wherein the well layer and the barrier layer are alternately stacked and arranged periodically, and the periodically arranged structure is arranged between the confinement layers, and the well layer material of the multi-quantum well structure is (Al2O3) lattice-matched with the epitaxial substrate. x Ga 1-x ) 0.5 In 0.5 For P material, the range of x is 0-0.

56.

12. The multi-junction solar cell according to claim 1, wherein the multi-quantum well structure comprises a confinement layer, a well layer, and a barrier layer, wherein the well layer and the barrier layer are alternately stacked in a periodic arrangement, and the periodic arrangement structure is arranged between the confinement layers, and the barrier layer material of the multi-quantum well structure is selected from AlInP or (Al2O3) that matches the lattice of the epitaxial substrate. x Ga 1-x ) 0.5 In 0.5 For P materials, x ranges from 0.56 to 1.

13. The multi-junction solar cell according to claim 1, wherein the multi-quantum well structure comprises a confinement layer, a well layer, and a barrier layer, wherein the well layer and the barrier layer are alternately stacked in a periodic arrangement, and the periodic arrangement structure is arranged between the confinement layers, and the multi-quantum well structure adopts a relatively low n-type doping, with a doping concentration of 1x10 17 cm -3 Up to 1x10 18 cm -3 .

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