Lattice mismatched four-junction quantum well solar cell

Abstract

The application discloses a lattice mismatch four-junction quantum well solar cell, which comprises, from bottom to top, a GaAs substrate, a GaAs buffer layer, a Ga 0.5 In 0.5 P barrier layer, a GaAs contact layer, a (Al h Ga 1‑h ) 0.5 In 0.5 P cell, a first tunnel junction, an Al y Ga 1‑y As cell, a second tunnel junction, a GaAs cell containing a quantum well structure, a third tunnel junction, a lattice-graded buffer layer, a Ga 1‑x In x As cell, a Bragg reflector DBR and a cap layer. 0.5 In 0.5 The GaAs cell contains an n-type doped n-GaAs emitter region or an n-Ga 1‑e P e / Ga 1‑f In f As quantum well and a p-type doped p-GaAs base region. The GaAs cell contains a quantum well structure, the application can expand the absorption spectrum of the GaAs cell and improve quantum efficiency without changing the lattice constant; the lattice-graded buffer layer is combined with the DBR, so that the anti-radiation capability and the crystal quality are improved, and the growth time is reduced.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a lattice-mismatched four-junction quantum well solar cell. Background Technology

[0002] Lattice-matched triple-junction solar cells (GaInP / GaAs / Ge) are widely used in solar arrays for satellites and spacecraft due to their excellent performance and reliability. However, the mismatch between the bandgap combination and the solar spectrum has led to a photoelectric conversion efficiency approaching the theoretical limit. To further improve performance, methods such as lattice-mismatch epitaxy, semiconductor bonding, and quantum well structures can be used to improve the matching degree between the bandgap combination and the solar spectrum, thereby enhancing the overall photoelectric conversion efficiency of the solar cell. Summary of the Invention

[0003] The purpose of this invention is to address the technical deficiencies in the existing technology by providing a lattice-mismatched four-junction quantum well solar cell, which features high photoelectric conversion efficiency, large production volume, and high cell operation stability, and can be directly used as a complete cell.

[0004] The technical solution adopted to achieve the purpose of this invention is:

[0005] A lattice-mismatched four-junction quantum well solar cell, comprising, from bottom to top: a GaAs substrate, a GaAs buffer layer, and a GaAs core. 0.5 In 0.5 P-blocking layer, GaAs contact layer, (Al) h Ga 1-h ) 0.5 In 0.5 P-cell, first tunnel junction, Al y Ga 1-y As battery, second tunnel junction, GaAs battery containing quantum well structure, third tunnel junction, lattice gradient buffer layer, Ga 1-x In x As the battery, Bragg reflector (DBR), and cap layer; where:

[0006] The GaAs solar cell includes an n-type doped n-GaAs emitter region or an n-Ga... 0.5 In 0.5 P-emission region, GaAs 1-e P e / Ga 1-f In f As quantum wells and p-type doped p-GaAs base regions.

[0007] The GaAsP / GaInAs quantum well is a stress-balanced structure that can extend the absorption spectrum of GaAs cells without changing the lattice constant, thereby improving the quantum efficiency of GaAs cells.

[0008] In the above technical solutions, GaAs 1-e P e / Ga 1-f In f In an As quantum well, 0.3 ≤ e ≤ 0.7 and 0.01 ≤ f ≤ 0.3 are used, with a doping concentration of 1 × 10⁻⁶. 16 ~1×10 19 cm -3 The thickness ranges from 30nm to 3000nm.

[0009] In the above technical solution, the Ga 0.5 In 0.5 The p-blocking layer is n-type doped Ga. 0.5 In 0.5 P-blocking layer, with a doping concentration of 1×10⁻⁶ 17 ~1×10 19 cm -3 The thickness ranges from 50nm to 500nm;

[0010] The GaAs contact layer is an n-type doped GaAs contact layer with a doping concentration of 1×10⁻⁶. 18 ~1×10 21 cm -3 The thickness ranges from 50nm to 500nm.

[0011] In the above technical solution, the (Al) h Ga 1-h ) 0.5 In 0.5 P-cells include n-type doped n-(Al) cells. h Ga 1-h ) 0.5 In 0.5 P-emitter region and p-type doped p-(Al) h Ga 1-h ) 0.5 In 0.5 P-base region, where 0.1≤h≤0.5, the (Al) h Ga 1-h ) 0.5 In 0.5 P-emission region and p-(Al) h Ga 1-h ) 0.5 In 0.5 The doping concentration of the P-base region is 1×10⁻⁶. 16 ~1×10 19 cm-3 The thickness ranges from 10nm to 1000nm.

[0012] In the above technical solution, the Al y Ga 1-y As batteries include n-type doped n-Al. y Ga 1-y As emitter layer and p-type doped p-Al y Ga 1-y As base region layer, where 0.1≤y≤0.5, the Al y Ga 1-y The doping concentration of both the emitter layer and the base layer in the As battery is 1×10⁻⁶. 16 ~1×10 19 cm -3 The thickness ranges from 30nm to 3000nm.

[0013] In the above technical solution, the lattice gradient buffer layer is (Al) c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b AsDBR, where 0≤c≤0.5, 0.5≤d≤1, and 0≤b≤0.5, the In composition b varies from 0 to x from the initial layer to the target gradient layer, using an n-type dopant with a doping concentration of 1×10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 1000 to 4000 nm, and the number of periods ranges from 10 to 30. Within each period, (Al) c Ga 1-c ) 1-b In b The thickness range of As is 20-200 nm, (Al) d Ga 1-d ) 1-b In b The thickness of As ranges from 20 to 200 nm. It can reflect photons that pass through GaAs cells and be reabsorbed by the junction cell, thereby improving quantum efficiency and radiation resistance. At the same time, it reduces the impact of penetrating dislocations caused by lattice mismatch on the active region of the cell.

[0014] In the above technical solution, the In component b gradually changes from 0 to x linearly or nonlinearly from bottom to top. When it changes nonlinearly, the In component b in each layer of the nonlinearly graded mismatch layer is overcharged and adjusted according to the proportion i. i is 1%-40%. If i is too small, the effect is not obvious; if i is too large, it will introduce more defects. This can adjust or reduce the mismatch stress in each layer. In addition, when designing an overcharge layer with a DBR structure, the overcharge range of In in the material design of this layer can be reduced, releasing stress defects in the thin film material with a smaller overcharge, thereby growing a mismatch layer material with high crystal quality.

[0015] In the above technical solution, the Ga 1-x In x As batteries include n-type doped n-Ga 1-x In x As emitter layer or n-Ga 1-z In z P-emitter layer and p-type doped p-Ga 1-x In x As base region layer, where 0.1≤x≤0.5 and 0.5≤z≤1, the Ga 1-x In x The doping concentration of both the emitter layer and the base layer in the As battery is 1×10⁻⁶. 16 ~1×10 19 cm -3 The thickness ranges from 30nm to 3000nm.

[0016] In the above technical solution, the Bragg reflector DBR is (Al) c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1- x In x As a DBR, where 0≤c≤0.5, 0.5≤d≤1, and 0.1≤x≤0.5, a p-type dopant with a doping concentration of 1×10⁻⁶ is used. 17 -1×10 19 cm -3 The thickness ranges from 1000 to 4000 nm, and the number of periods ranges from 10 to 30. Within each period, (Al) c Ga 1-c ) 1-x In x The thickness range of As is 20-200 nm, (Al) d Ga 1-d ) 1-x In x The thickness of As ranges from 20 to 200 nm.

[0017] In the above technical solution, the first tunnel junction includes n-type doped n + -(Al h Ga 1-h ) 0.5 In 0.5 P-layer and p-type doped p + -Al y Ga 1-y Layer A, where 0.1 ≤ h ≤ 0.5 and 0.1 ≤ y ≤ 0.5, n + -(Al h Ga 1-h ) 0.5 In 0.5 P layer and p + -Al y Ga 1-y The doping concentration in the As layer is 1×10⁻⁶. 19 ~1×10 21 cm -3 The thickness ranges from 1 to 100 nm.

[0018] The second tunnel junction includes n-type doped n + -Ga 0.5 In 0.5 P-layer and p-type doped p + -Al y Ga 1-y Layer A, where 0.1 ≤ y ≤ 0.5, n + -Ga 0.5 In 0.5 P layer and p + -Al y Ga 1-y The As layer doping concentration is 1×10⁻⁶. 19 ~1×10 21 cm -3 The thickness ranges from 1 to 100 nm;

[0019] The third tunnel junction includes n-type doped n + -GaAs layer and p-type doped p + -Al y Ga 1-y Layer A, where 0.1 ≤ y ≤ 0.5, n + -GaAs layer and p + -Al y Ga 1-y The As layer doping concentration is 1×10⁻⁶. 19 -1×10 21 cm -3 The thickness ranges from 1 to 100 nm;

[0020] In the above technical solution, the cap layer is a p-type doped p-type layer. + -Ga 1-x In x An As layer, where 0.1 ≤ x ≤ 0.5, has a doping concentration of 1 × 10⁻⁶. 18 ~1×10 21 cm -3 The thickness ranges from 50nm to 500nm.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. Compared with traditional triple-junction solar cells, quadruple-junction solar cells have a better match between their bandgap combination and the solar spectrum, which can reduce photon absorption loss and thermal loss of photogenerated carriers.

[0023] 2. GaAs solar cells contain quantum well structures, which can expand the absorption spectrum of GaAs solar cells and improve quantum efficiency without changing the lattice constant;

[0024] 3. The lattice gradient buffer layer is combined with DBR, which can improve radiation resistance and crystal quality while reducing growth time;

[0025] 4. By adjusting the position of the center wavelength of the DBR (Distributed Bragg Reflector), the transmitted Ga wavelength can be reflected. 1-x In x As the photons of the cell are reabsorbed by the junction cell, thereby improving quantum efficiency and radiation resistance. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a lattice-mismatched four-junction quantum well solar cell structure according to the present invention.

[0027] Figure 2 This is a structural diagram of the nonlinear gradient mismatch layer region in Example 2, where i is the gradient callback rate.

[0028] In the figure: 1. GaAs substrate; 2. GaAs buffer layer; 3. Ga... 0.5 In 0.5 4. P-blocking layer; 5. GaAs contact layer; 6. (Al) h Ga 1-h ) 0.5 In 0.5 P-cell; 6. First tunnel junction; 7. Al y Ga 1-y 8. GaAs cell; 9. Second tunnel junction; 10. GaAs cell (including quantum well structure); 11. Third tunnel junction; 12. Lattice gradient buffer layer; 13. Ga 1-x In xAs a battery; 13. DBR (Draco Bragg reflector); 14. Cap layer. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0030] Example 1

[0031] Please see Figure 1 A lattice-mismatched four-junction quantum well solar cell includes a GaAs substrate, on which a GaAs buffer layer and a GaAs layer are sequentially formed. 0.5 In 0.5 P-blocking layer, GaAs contact layer, (Al) h Ga 1-h ) 0.5 In 0.5 P-cell, first tunnel junction, Al y Ga 1-y As solar cell, second tunnel junction, GaAs solar cell (including quantum well structure), third tunnel junction, lattice gradient buffer layer, Ga 1-x In x As a battery, a DBR (Distributed Bragg Reflector) and a cap layer. Its manufacturing process is as follows:

[0032] GaAs buffer layer 2 and GaAs substrate 3 were sequentially grown on GaAs substrate 1 using MOCVD (metal-organic chemical vapor deposition) technology. 0.5 In 0.5 P-barrier layer 3, GaAs contact layer 4, (Al) h Ga 1-h ) 0.5 In 0.5 P-cell 5, first tunnel junction 6, Al y Ga 1-y 7. As cell; 8. Second tunnel junction; 9. GaAs cell (including quantum well structure); 10. Third tunnel junction; 11. Lattice gradient buffer layer; 22. Ga... 1- x In x The specific manufacturing process of As battery 12, Bragg reflector (DBR) 13 and cap layer 14 is as follows:

[0033] The GaAs buffer layer has an n-type dopant of Si, Se, or Te, with a doping concentration of 1 × 10⁻⁶. 17 ~1×10 19 cm -3 The growth temperature is 600–750℃, and the thickness range is 100–1000 nm;

[0034] Ga 0.5 In0.5 The p-blocking layer has an n-type dopant of Si, Se, or Te, with a doping concentration of 1 × 10⁻⁶. 17 ~1×10 19 cm -3 The growth temperature is 600–750℃, and the thickness range is 50nm–500nm;

[0035] The GaAs contact layer has an n-type dopant of Si, Se, or Te, with a doping concentration of 1 × 10⁻⁶. 18 ~1×10 21 cm -3 The growth temperature is 550–700℃, and the thickness range is 50nm–500nm;

[0036] (Al h Ga 1-h ) 0.5 In 0.5 P-cells, including n-type doped n-(Al) cells. h Ga 1-h ) 0.5 In 0.5 P-emitter layer and p-type doped p-(Al) h Ga 1-h ) 0.5 In 0.5 The P-based region layer, wherein 0.1 ≤ h ≤ 0.5, is grown at a temperature of 600–800 °C, wherein the n-(Al) h Ga 1-h ) 0.5 In 0.5 The dopant of the P-emitter layer is Si, Se, or Te, with a doping concentration of 1 × 10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 10 nm to 100 nm; the p-(Al) h Ga 1-h ) 0.5 In 0.5 The dopant of the P-based region is Zn, Mg, or C, with a doping concentration of 1 × 10⁻⁶. 16 -1×10 18 cm -3 The thickness ranges from 100nm to 1000nm;

[0037] The first tunnel junction includes n-type doped n + -(Al h Ga 1-h ) 0.5 In 0.5 P-layer and p-type doped p + -Al y Ga 1-yThe As layer is grown at a temperature of 500–700℃, wherein the n + -(Al h Ga 1-h ) 0.5 In 0.5 In the P-layer, where 0.1 ≤ h ≤ 0.5, the dopant is Si, Se, or Te, and the doping concentration is 1 × 10⁻⁶. 19 -1×10 21 cm -3 The thickness ranges from 1 to 100 nm; the p + -Al y Ga 1-y An As layer, where 0.1 ≤ y ≤ 0.5, with Zn, Mg, or C as the dopant and a doping concentration of 1 × 10⁻⁶. 19 -1×10 21 cm -3 The thickness ranges from 1 to 100 nm;

[0038] Al y Ga 1-y As batteries, including n-type doped n-Al y Ga 1-y As(n-(Al h Ga 1-h ) 0.5 In 0.5 P) Emitter layer and p-type doped p-Al y Ga 1-y The As-based region layer, wherein 0.1≤y≤0.5 and 0.1≤h≤0.5, is grown at a temperature of 600–800℃; wherein the n-Al y Ga 1-y As(n-(Al h Ga 1-h ) 0.5 In 0.5 P) The dopant of the emitter layer is Si, Se, or Te, with a doping concentration of 1×10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 30nm to 300nm; the p-Al y Ga 1-y The As base layer is doped with Zn, Mg, or C, with a doping concentration of 1 × 10⁻⁶. 16 -1×10 18 cm -3 The thickness ranges from 300nm to 3000nm;

[0039] The second tunnel junction includes n-type doped n + -Ga 0.5 In 0.5P-layer and p-type doped p + -Al y Ga 1-y The As layer is grown at a temperature of 500–700℃, wherein the n + -Ga 0.5 In 0.5 The dopant of the P layer is Si, Se, or Te, with a doping concentration of 1 × 10⁻⁶. 19 -1×10 21 cm -3 The thickness ranges from 1 to 100 nm; the p + -Al y Ga 1-y The As layer is doped with Zn, Mg, or C, with a doping concentration of 1 × 10⁻⁶. 19 -1×10 21 cm -3 , 0.1≤y≤0.5, thickness range is 1-100nm;

[0040] GaAs solar cells, including n-type doped n-GaAs (n-Ga 0.5 In 0.5 P) Launch area, GaAs 1-e P e / Ga 1-f In f The growth temperature is 600–800 °C for the As quantum well and the p-type doped p-GaAs base region; wherein the n-GaAs (or n-GaAs) is a quantum well and a p-type doped p-GaAs base region; 0.5 In 0.5 P) The dopant of the emitter layer is Si, Se, or Te, with a doping concentration of 1×10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 30 to 300 nm; wherein the GaAs 1-e P e / Ga 1-f In f As quantum wells, with 0.3≤e≤0.7 and 0.01≤f≤0.3, a thickness ranging from 300-3000 nm, and a period number ranging from 10-100, wherein within each period, GaAs... 1-e P e The thickness range is 1-100 nm, Ga 1-f In f The thickness of the As layer ranges from 1 to 100 nm; the dopant of the p-GaAs base layer is Zn, Mg, or C, and the doping concentration is 1 × 10⁻⁶. 16 -1×10 18 cm -3 The thickness ranges from 200 to 2000 nm;

[0041] The third tunnel junction includes n-type doped n + -GaAs layer and p-type doped p + -Al y Ga 1-y The As layer is grown at a temperature of 550–700℃, where n + The GaAs layer is doped with Si, Se, or Te, with a doping concentration of 1 × 10⁻⁶. 19 -1×10 21 cm -3 The thickness ranges from 1 to 100 nm; where p + -Al y Ga 1-y The dopant of the As layer is Zn, Mg, or C, with 0.1 ≤ y ≤ 0.5 and a doping concentration of 1 × 10⁻⁶. 19 -1×10 21 cm -3 The thickness ranges from 1 to 100 nm;

[0042] The lattice gradient buffer layer is (Al) c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As DBR, where 0≤c≤0.5, 0.5≤d≤1, and 0≤b≤0.5, the In composition b linearly changes from 0 to x from bottom to top, and the dopant used is Si, Se, or Te with a doping concentration of 1×10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 1000 to 4000 nm, and the number of periods ranges from 10 to 30. Within each period, (Al) c Ga 1-c ) 1-b In b The thickness range of As is 20-200 nm, (Al) d Ga 1-d ) 1-b In b The thickness of As ranges from 20 to 200 nm, and the growth temperature is 600–800 °C.

[0043] Ga 1-x In x As batteries, including n-type doped n-Ga 1-x In x As (or n-Ga 1-z In z P) Emitter layer and p-type doped p-Ga1-x In x The As-based region layer, wherein 0.1≤x≤0.5 and 0.5≤z≤1, is grown at a temperature of 600–800℃; wherein the n-Ga 1-x In x As (or n-Ga 1-z In z P) The dopant of the emitter layer is Si, Se, or Te, with a doping concentration of 1 × 10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 30 to 300 nm; the p-Ga 1-x In x The As base layer is doped with Zn, Mg, or C, with a doping concentration of 1 × 10⁻⁶. 16 -1×10 18 cm -3 The thickness ranges from 300 to 3000 nm;

[0044] (Al c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As a DBR, where 0≤c≤0.5, 0.5≤d≤1, and 0.1≤x≤0.5, the dopant is Zn, Mg, or C, and the doping concentration is 1×10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 1000 to 4000 nm, and the number of periods ranges from 10 to 30. Within each period, (Al) c Ga 1-c ) 1-x In x The thickness range of As is 20-200 nm, (Al) d Ga 1-d ) 1-x In x The thickness of As ranges from 20 to 200 nm, and the growth temperature is 600–800 °C.

[0045] The cap layer is p-type doped Ga 1-x In x As, where 0.1 ≤ x ≤ 0.5, the dopant is Zn, Mg or C, and the doping concentration is 1 × 10⁻⁶. 18 -1×10 21 cm -3 The thickness ranges from 50nm to 500nm, and the growth temperature is 550–700℃.

[0046] The total time required for the growth of the above-mentioned material layers is 3-7 hours. The subsequent reverse device process is a well-known technology.

[0047] By implementing the above steps, the fabrication process of the AlGaInP / AlGaAs / GaAs(QW) / GaInAs lattice-mismatched four-junction quantum well solar cell of the present invention is completed.

[0048] Example 2

[0049] The difference between this embodiment and Embodiment 1 is that the lattice gradient buffer layer is (Al). c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b In the As DBR, the component b of In transitions nonlinearly from 0 to x from the initial layer to the target gradient layer, such as... Figure 2 As shown, the component b of each In layer in the nonlinear graded mismatch layer is overshoot-corrected according to the ratio i. i ranges from 1% to 40%. When i is too small, the effect is not obvious, while when it is too large, it will introduce more defects. Nonlinear overshoot correction can further optimize the performance of solar cells.

[0050] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A lattice-mismatched four-junction quantum well solar cell, characterized in that, From bottom to top, the layers consist of: GaAs substrate, GaAs buffer layer, and GaAs... 0.5 In 0.5 P-blocking layer, GaAs contact layer, (Al) h Ga 1-h ) 0.5 In 0.5 P-cell, first tunnel junction, Al y Ga 1- y As battery, second tunnel junction, GaAs battery containing quantum well structure, third tunnel junction, lattice gradient buffer layer, Ga 1- x In x As the battery, Bragg reflector (DBR), and cap layer; where: The GaAs solar cell includes an n-type doped n-GaAs emitter region or an n-Ga... 0.5 In 0.5 P-emission region, GaAs 1-e P e / Ga 1- f In f As quantum wells and p-type doped p-GaAs base regions.

2. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, GaAs 1-e P e / Ga 1- f In f In an As quantum well, 0.3 ≤ e ≤ 0.7 and 0.01 ≤ f ≤ 0.3 are used, with a doping concentration of 1 × 10⁻⁶. 16 ~1×10 19 cm -3 The thickness ranges from 30nm to 3000nm.

3. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, The Ga 0.5 In 0.5 The p-blocking layer is n-type doped Ga. 0.5 In 0.5 P-blocking layer, with a doping concentration of 1×10⁻⁶ 17 ~1×10 19 cm -3 The thickness ranges from 50nm to 500nm; The GaAs contact layer is an n-type doped GaAs contact layer with a doping concentration of 1×10⁻⁶. 18 ~1×10 21 cm -3 The thickness ranges from 50nm to 500nm.

4. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, The (Al) h Ga 1-h ) 0.5 In 0.5 P-cells include n-type doped n-(Al) cells. h Ga 1-h ) 0.5 In 0.5 P-emitter layer and p-type doped p-(Al) h Ga 1-h ) 0.5 In 0.5 P-based region layer, where 0.1≤h≤0.5, the (Al) h Ga 1-h ) 0.5 In 0.5 The doping concentration of both the emitter and base layers of the P-cell is 1×10⁻⁶. 16 ~1×10 19 cm -3 The thickness ranges from 10nm to 1000nm.

5. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, The Al y Ga 1-y As batteries include n-type doped n-Al. y Ga 1-y As emitter layer and p-type doped p-Al y Ga 1-y As base region layer, where 0.1≤y≤0.5, the Al y Ga 1-y The doping concentration of both the emitter layer and the base layer in the As battery is 1×10⁻⁶. 16 ~1×10 19 cm -3 The thickness ranges from 30nm to 3000nm.

6. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, The lattice gradient buffer layer is (Al) c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As a DBR, where 0≤c≤0.5, 0.5≤d≤1, and 0≤b≤0.5, the In composition b varies from 0 to x from the initial layer to the target gradient layer, using an n-type dopant with a doping concentration of 1×10⁻⁶. 17 -1×10 19 cm -3 The thickness ranges from 1000 to 4000 nm, and the number of periods ranges from 10 to 30. Within each period, (Al) c Ga 1-c ) 1- b In b The thickness range of As is 20-200 nm, (Al) d Ga 1-d ) 1-b In b The thickness of As ranges from 20 to 200 nm.

7. The lattice-mismatched four-junction quantum well solar cell as described in claim 6, characterized in that, The component b of In gradually changes from 0 to x from bottom to top, either linearly or nonlinearly. When it changes nonlinearly, the component b of each In layer in the nonlinearly changed mismatch layer is overshooted and corrected according to the proportion i, where i is 1%-40%.

8. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, The Ga 1-x In x As batteries include n-type doped n-Ga 1-x In x As emitter layer or n-Ga 1-z In z P-emitter layer and p-type doped p-Ga 1-x In x As base region layer, where 0.1≤x≤0.5 and 0.5≤z≤1, the Ga 1-x In x The doping concentration of both the emitter layer and the base layer in the As battery is 1×10⁻⁶. 16 ~1×10 19 cm -3 The thickness ranges from 30nm to 3000nm.

9. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, The Bragg reflector DBR is (Al) c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As a DBR, where 0≤c≤0.5, 0.5≤d≤1, and 0.1≤x≤0.5, a p-type dopant with a doping concentration of 1×10⁻⁶ is used. 17 -1×10 19 cm -3 The thickness ranges from 1000 to 4000 nm, and the number of periods ranges from 10 to 30. Within each period, (Al) c Ga 1-c ) 1-x In x The thickness range of As is 20-200 nm, (Al) d Ga 1-d ) 1-x In x The thickness of As ranges from 20 to 200 nm.

10. The lattice-mismatched four-junction quantum well solar cell as described in claim 1, characterized in that, The first tunnel junction includes n-type doped n + -(Al h Ga 1-h ) 0.5 In 0.5 P-layer and p-type doped p + -Al y Ga 1-y Layer A, where 0.1 ≤ h ≤ 0.5 and 0.1 ≤ y ≤ 0.5, n + -(Al h Ga 1-h ) 0.5 In 0.5 P layer and p + -Al y Ga 1-y The doping concentration in the As layer is 1×10⁻⁶. 19 ~1×10 21 cm -3 The thickness ranges from 1 to 100 nm. The second tunnel junction includes n-type doped n + -Ga 0.5 In 0.5 P-layer and p-type doped p + -Al y Ga 1-y Layer A, where 0.1 ≤ y ≤ 0.5, n + -Ga 0.5 In 0.5 P layer and p + -Al y Ga 1-y The As layer doping concentration is 1×10⁻⁶. 19 ~1×10 21 cm -3 The thickness ranges from 1 to 100 nm. The third tunnel junction includes n-type doped n + -GaAs layer and p-type doped p + -Al y Ga 1-y Layer A, where 0.1 ≤ y ≤ 0.5, n + -GaAs layer and p + -Al y Ga 1-y The As layer doping concentration is 1×10⁻⁶. 19 -1×10 21 cm -3 The thickness ranges from 1 to 100 nm. The cap layer is p-type doped p + -Ga 1-x In x An As layer, where 0.1 ≤ x ≤ 0.5, has a doping concentration of 1 × 10⁻⁶. 18 ~1×10 21 cm -3 The thickness ranges from 50nm to 500nm.

Images