Forward lattice mismatch five-junction quantum well solar cell

Abstract

The invention discloses a forward lattice mismatch five-junction quantum well solar cell which comprises a germanium substrate. The solar cell sequentially comprises a Ga < 0.5 > In < 0.5 > P nucleating layer, a Ga < 0.99 > In < 0.01 > As buffer layer, a first tunnel junction, a lattice gradient buffer layer (Al < c > Ga < 1-c >) < 1-b > In As / (Al < d > Ga < 1-d >) < 1-b > In As DBR, a Ga < 1-x > In < x > As cell comprising a quantum well structure, a second tunnel junction, a (Al < c > Ga < 1-c >) < 1-x > In < x > As / (Al < d > Ga < 1-d >) < 1-x > In < x > As DBR, a (Al < e > Ga < 1-e >) < 1-x > In < x > As cell or a Ga < 1-x > In < x > According to the lattice mismatch five-junction quantum well solar cell prepared by the method, the band gap is 2.0 / 1.7 / 1.4 / 1.1 (quantum well) / 0.7 (eV), the theoretical efficiency reaches 56.2%, compared with a semiconductor bonding five-junction solar cell in an American spectrum laboratory, the lattice mismatch is smaller, the open-circuit voltage is higher, meanwhile, due to the introduction of the quantum well structure, the short-circuit current cannot be reduced, and the theoretical efficiency is higher.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cell structures, and in particular relates to a forward lattice mismatched five-junction quantum well solar cell. Background Art

[0002] Ordinary single-junction solar cells can only absorb a portion of the light in the entire solar spectrum, while the multi-junction stacked structure is equivalent to dividing the solar spectrum into several segments, and each sub-cell absorbs the spectrum closest to its band gap, which not only increases the absorption rate of the low-energy end spectrum, but also reduces the thermal loss of high-energy photons. Therefore, the more cell junctions are connected in series, the higher the conversion efficiency. Table 1 shows the theoretical efficiency of solar cells with different band gap combinations with lattice mismatch.

[0003] Table 1 Theoretical efficiency of solar cells with different band gap combinations

[0004] Serial number structure Band Gap Theoretical efficiency 1 Lattice-mismatched triple-junction solar cells 1.8 / 1.3 / 0.7(eV) 48.5％ 2 Lattice-mismatched four-junction solar cell 1.9 / 1.4 / 1.0 / 0.7(eV) 52.3％ 3 Lattice-mismatched five-junction solar cell 2.0 / 1.7 / 1.3 / 1.0 / 0.7(eV) 54.8％

[0005] It can be seen from Table 1 that due to the more reasonable division of the spectrum by the lattice mismatch five-junction solar cell, a higher theoretical efficiency can be obtained, which is 54.8%. Summary of the invention

[0006] The present invention provides a forward lattice mismatched five-junction quantum well solar cell which has high external quantum efficiency, high photoelectric conversion efficiency, long service life, high battery operation stability and can be directly used as a complete battery.

[0007] The specific technical solution adopted by the present invention is: a forward lattice mismatched five-junction quantum well solar cell, comprising a germanium substrate, Ga 0.5 In 0.5 P nucleation layer, Ga 0.99 In 0.01 As buffer layer, first tunnel junction, (Al c Ga 1-c ) 1- b In b As / (Al d Ga 1-d ) 1-b In b As DBR (lattice gradient buffer layer), Ga 1-x In x As battery (including quantum well structure), second tunnel junction, (Al c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-xIn x As DBR, (Al e Ga 1-e ) 1-x In x As battery (or Ga 1-x In x AsP battery), the third tunnel junction, Ga 1-y In y P cell (or (AlGa) 1-x In x As battery), the fourth tunnel junction, (Al f Ga 1-f ) 1-y In y P cell and cap layer.

[0008] The c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As DBR (lattice gradient buffer layer), where 0≤c≤0.5, 0.5≤d≤1 and 0.01≤b≤0.5, the component b of In is gradually changed from 0.01 to x from bottom to top, and p-type dopant is used with a doping concentration of 1×10 17 -1×10 19 cm -3 , the thickness ranges from 1000-8000nm, the number of periods ranges from 10-40, and within each period, (Al c Ga 1-c ) 1-b In b The thickness of As is in the range of 20-200 nm, (Al d Ga 1-d ) 1-b In b As has a thickness range of 20-200nm and can reflect and transmit Ga 1-x In x The photons of the As cell are reabsorbed by the junction cell, thereby improving the quantum efficiency and radiation resistance, while reducing the impact of threading dislocations caused by lattice mismatch on the active area of ​​the cell.

[0009] The Ga 1-x In x As cells include n-type doped n-Ga 1-x In x As (or n-Ga 1-y In y P) emitter layer, Ga1- r In r As / Ga 1-z In z As quantum well and p-type doped p-Ga 1-x In x As base layer, wherein 0.01≤x≤0.5, 0.01≤r≤0.4 and 0.01≤z≤0.6; wherein the n-Ga 1-x In x As (or n-Ga 1-y In y The doping concentration of the emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 20 to 200 nm; the p-Ga 1-x In x The doping concentration of the As base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 300-3000nm. Ga 1-r In r As / Ga 1-z In z The As quantum well is a stress-balanced structure that can expand the absorption spectrum of the GaInAs battery without changing the lattice constant, thereby improving the quantum efficiency of the GaInAs battery.

[0010] The c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As DBR, where 0≤c≤0.5, 0.5≤d≤1 and 0.01≤x≤0.5, uses p-type dopant with a doping concentration of 1×10 17 -1×10 19 cm -3 , the thickness ranges from 1000-4000nm, the number of periods ranges from 3-30, and within each period, (Al c Ga 1-c ) 1-x In x The thickness of As is in the range of 10-100 nm, (Al d Ga 1-d ) 1-x In x As has a thickness range of 10-100nm and can be reflected and transmitted (Ale Ga 1-e ) 1-x In x The photons of the As cell are reabsorbed by the junction cell, thereby improving the quantum efficiency and radiation resistance.

[0011] The e Ga 1-e ) 1-x In x As battery (or Ga 1-x In x AsP cells) include n-doped n-(Al e Ga 1-e ) 1- x In x As (or n-Ga 1-x In x AsP) emitter layer and p-doped p-(Al e Ga 1-e ) 1-x In x As(or p-Ga 1-x In x AsP) base layer, wherein 0.1≤e≤0.6 and 0.01≤x≤0.5; wherein the n-(Al e Ga 1-e ) 1-x In x As (or n-Ga 1-x In x The doping concentration of the AsP emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 20 to 200 nm; the p-(Al e Ga 1-e ) 1-x In x As(or p-Ga 1-x In x The doping concentration of the AsP base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 300-3000nm.

[0012] The Ga 1-y In y P cell (or (AlGa) 1-x In x As cells) include n-type doped n-Ga 1-y In y P(or n-(AlGa)1-x In x As) emitter layer and p-type doped p-Ga 1-y In y P (or p-(AlGa) 1-x In x As) base layer, wherein 0.4≤y≤0.9; wherein the n-Ga 1-y In y P(or n-(AlGa) 1-x In x The doping concentration of the emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 2 to 200 nm; the p-Ga 1-y In y P (or p-(AlGa) 1-x In x The doping concentration of the As base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 100-2000nm.

[0013] The f Ga 1-f ) 1-y In y The P cell includes n-type doped n-(Al f Ga 1-f ) 1-y In y P emitter layer and p-type doped p-(Al f Ga 1-f ) 1-y In y P base layer, wherein 0.1≤f≤0.6 and 0.4≤y≤0.9; wherein the n-(Al f Ga 1-f ) 1- y In y The doping concentration of the P emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 2 to 200 nm; the p-(Al f Ga 1-f ) 1- y In y The doping concentration of the P base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 100-2000nm.

[0014] The first tunnel junction includes an n-type doped n + -GaAs layer and p-type doped p + -Al g Ga 1-g As layer; wherein said n + The doping concentration of the GaAs layer is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -Al g Ga 1-g The doping concentration of the As layer is 1×10 19 -1×10 21 cm -3 , 0.1≤g≤0.6, thickness range is 1-100nm.

[0015] The second tunnel junction includes an n-type doped n + -Ga 1-y In y P layer and p-type doped p + -(Al e Ga 1-e ) 1-x In x As layer, wherein the n + -Ga 1-y In y P layer, 0.4≤y≤0.9, doping concentration is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -(Al e Ga 1-e ) 1-x In x As layer, 0.1≤e≤0.6 and 0.01≤x≤0.5, doping concentration is 1×10 19 -1×10 21 cm -3 , thickness range is 1-100nm.

[0016] The third tunnel junction includes an n-type doped n + -Ga 1-y In y P layer and p-type doped p + -(Al h Ga 1-h ) 1-x In x As layer, wherein the n +-Ga 1-y In y P layer, 0.4≤y≤0.9, doping concentration is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -(Al h Ga 1-h ) 1-x In x As layer, 0.2≤h≤0.7 and 0.01≤x≤0.5, doping concentration is 1×10 19 -1×10 21 cm -3 , thickness range is 1-100nm.

[0017] The fourth tunnel junction includes an n-type doped n + -(Al f Ga 1-f ) 1-y In y P layer and p-type doped p + -(Al i Ga 1-i ) 1-x In x As layer, wherein the n + -(Al f Ga 1-f ) 1-y In y P layer, 0.1≤f≤0.6 and 0.4≤y≤0.9, doping concentration is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -(Al i Ga 1-i ) 1-x In x As layer, 0.3≤i≤0.8 and 0.01≤x≤0.5, doping concentration is 1×10 19 -1×10 21 cm -3 , thickness range is 1-100nm.

[0018] The cap layer is n-type doped + -Ga 1-x In x As, where 0.01≤x≤0.5, the doping concentration is 1×10 18 -1×10 21 cm -3 , thickness range is 10-1000nm.

[0019] The advantages and positive effects of the present invention are:

[0020] 1. The present invention adopts a forward lattice mismatched five-junction quantum well solar cell, whose device and assembly process are exactly the same as those of a forward matched three-junction solar cell, and is easy to manufacture;

[0021] 2. The theoretical conversion efficiency of this structure can reach more than 56%, and it can be directly used as a complete solar cell;

[0022] 3. Introducing a stress-balanced quantum well structure into GaInAs cells can expand the absorption spectrum of GaInAs cells without changing the lattice constant, thereby improving the quantum efficiency of GaInAs cells;

[0023] 4. The combination of DBR and lattice gradient buffer layer improves radiation resistance and crystal quality while reducing growth time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 4 is a structural diagram of a preferred embodiment of the present invention.

[0025] In the figure: 1. Germanium substrate; 2. Ga 0.5 In 0.5 P nucleation layer; 3. Ga 0.99 In 0.01 As buffer layer; 4. first tunnel junction; 5. (Al c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As DBR (lattice gradient buffer layer); 6. Ga 1-x In x As battery (including quantum well structure); 7. Second tunnel junction; 8. (Al c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As DBR; 9, (Al e Ga 1-e ) 1-x In x As battery (or Ga 1-x In x AsP battery); 10. Third tunnel junction; 11. Ga 1-y Iny P cell (or (AlGa) 1-x In x As battery); 12. Fourth tunnel junction; 13. (Al f Ga 1-f ) 1-y In y P battery; 14. cap layer. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] On the contrary, the present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the detailed description of the present invention below. Those skilled in the art can fully understand the present invention without the description of these details.

[0028] Figure 1 The forward lattice mismatched five-junction quantum well solar cell provided by the embodiment of the present invention comprises a germanium substrate, and from bottom to top, Ga 0.5 In 0.5 P nucleation layer, Ga 0.99 In 0.01 As buffer layer, first tunnel junction, (Al c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As DBR (lattice gradient buffer layer), Ga 1-x In x As battery (including quantum well structure), second tunnel junction, (Al c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As DBR, (Al e Ga 1-e ) 1-x In x As battery (or Ga 1-x In xAsP battery), the third tunnel junction, Ga 1-y In y P cell (or (AlGa) 1-x In x As battery), the fourth tunnel junction, (Al f Ga 1-f ) 1-y In y P battery and cap layer. Its production process is:

[0029] Metal organic chemical vapor deposition (MOCVD) is used to sequentially grow Ga on the germanium substrate 1. 0.5 In 0.5 P nucleation layer 2, Ga 0.99 In 0.01 As buffer layer 3, first tunnel junction 4, (Al c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As DBR (lattice gradient buffer layer) 5, Ga 1-x In x As battery (including quantum well structure) 6, second tunnel junction 7, (Al c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As DBR 8, (Al e Ga 1-e ) 1-x In x As battery (or Ga 1-x In x AsP battery) 9, the third tunnel junction 10, Ga 1-y In y P cell (or (AlGa) 1-x In x As battery) 11, the fourth tunnel junction 12, (Al f Ga 1-f ) 1-y In y The specific manufacturing process of P battery 13 and cap layer 14 is as follows:

[0030] Ga 0.5 In 0.5P nucleation layer, whose n-type dopant is Si, Se or Te, has a growth temperature of 500–700°C and a thickness range of 10-1000nm. The n-Ge layer is formed by the diffusion of phosphorus atoms in this layer, thus forming a germanium cell;

[0031] Ga 0.99 In 0.01 As buffer layer, whose n-type dopant is Si, Se or Te, grown at 600–800°C and with a thickness ranging from 200 to 2000 nm;

[0032] The first tunnel junction includes an n-type doped n + -GaAs layer and p-type doped p + -Al g Ga 1-g As layer, where n + -GaAs layer is doped with Si, Se or Te, with a doping concentration of 1×10 19 -1×10 21 cm -3 , thickness range is 1-100nm, growth temperature is 500–700℃; among which p + -Al g Ga 1-g The dopant of the As layer is Zn, Mg or C, and the doping concentration is 1×10 19 -1×10 21 cm -3 , 0.1≤g≤0.6, thickness range 1-100nm, growth temperature 500–700℃;

[0033] The c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As DBR (lattice gradient buffer layer), where 0≤c≤0.5, 0.5≤d≤1 and 0.01≤b≤0.5, the component b of In changes from 0.01 to x from bottom to top, and the dopant used is Zn, Mg or C, with a doping concentration of 1×10 17 -1×10 19 cm -3 , the thickness ranges from 1000-8000nm, the number of periods ranges from 10-40, and within each period, (Al c Ga 1-c ) 1-b In b The thickness of As is in the range of 20-200 nm, (Al d Ga1-d ) 1-b In b The thickness of As ranges from 20 to 200 nm, and the growth temperature is 600–800 °C;

[0034] Ga 1-x In x As cells, including n-type doped n-Ga 1-x In x As (or n-Ga 1-y In y P) emitter layer, Ga 1- r In r As / Ga 1-z In z As quantum well and p-type doped p-Ga 1-x In x As base layer, wherein 0.01≤x≤0.5, 0.01≤r≤0.4 and 0.01≤z≤0.6; wherein the n-Ga 1-x In x As (or n-Ga 1-y In y The dopant of the emitter layer is Si, Se or Te, and the doping concentration is 1×10 17 -1×10 19 cm -3 , with a thickness range of 20-200nm and a growth temperature of 600–800°C; wherein the Ga 1-r In r As / Ga 1-z In z As quantum well, thickness ranges from 400-4000nm, the number of periods ranges from 20-200, and in each period, Ga 1-e In e The thickness of As is in the range of 2-200nm, and Ga 1-f In f The thickness of As is in the range of 2-200 nm; the p-Ga 1-x In x The dopant of the As base layer is Zn, Mg or C, and the doping concentration is 1×10 16 -1×10 18 cm -3 , thickness range is 300-3000nm, growth temperature is 600–800℃;

[0035] The second tunnel junction includes an n-type doped n + -Ga 1-y In y P layer and p-type doped p + -(Ale Ga 1-e ) 1-x In x As layer, wherein the n + -Ga 1-y In y The dopant of the P layer is Si, Se or Te, and the doping concentration is 1×10 19 -1×10 21 cm -3 , 0.4≤y≤0.9, thickness range is 1-100nm, growth temperature is 500–700℃; the p + -(Al e Ga 1-e ) 1-x In x The dopant of the As layer is Zn, Mg or C, and the doping concentration is 1×10 19 -1×10 21 cm -3 , 0.1≤e≤0.6 and 0.01≤x≤0.5, thickness range 1-100nm, growth temperature 500–700℃;

[0036] (Al c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As DBR, where 0≤c≤0.5, 0.5≤d≤1 and 0.01≤x≤0.5, using dopants of Zn, Mg or C with a doping concentration of 1×10 17 -1×10 19 cm -3 , the thickness ranges from 1000-4000nm, the number of periods ranges from 3-30, and within each period, (Al c Ga 1-c ) 1-x In x The thickness of As is in the range of 10-100 nm, (Al d Ga 1-d ) 1-x In x The thickness of As ranges from 10 to 100 nm, and the growth temperature is 600–800 °C;

[0037] (Al e Ga 1-e ) 1-x In x As battery (or Ga 1-x In xAsP cells), including n-doped n-(Al e Ga 1-e ) 1-x In x As (or n-Ga 1-x In x AsP) emitter layer and p-doped p-(Al e Ga 1-e ) 1-x In x As(or p-Ga 1-x In x AsP) base layer, wherein 0.1≤e≤0.6 and 0.01≤x≤0.5; wherein the n-(Al e Ga 1-e ) 1-x In x As (or n-Ga 1-x In x AsP) emitter layer is doped with Si, Se or Te, with a doping concentration of 1×10 17 -1×10 19 cm -3 , with a thickness range of 20-200nm and a growth temperature of 600–800°C; the p-(Al e Ga 1-e ) 1-x In x As(or p-Ga 1-x In x AsP) base layer is doped with Zn, Mg or C, with a doping concentration of 1×10 16 -1×10 18 cm -3 , thickness range is 300-3000nm, growth temperature is 600–800℃;

[0038] The third tunnel junction includes an n-type doped n + -Ga 1-y In y P layer and p-type doped p + -(Al h Ga 1-h ) 1-x In x As layer, wherein the n + -Ga 1-y In y The dopant of the P layer is Si, Se or Te, and the doping concentration is 1×10 19 -1×10 21 cm -3 , 0.4≤y≤0.9, thickness range is 1-100nm, growth temperature is 500–700℃; the p+ -(Al h Ga 1-h ) 1-x In x The dopant of the As layer is Zn, Mg or C, and the doping concentration is 1×10 19 -1×10 21 cm -3 , 0.2≤h≤0.7 and 0.01≤x≤0.5, thickness range 1-100nm, growth temperature 500–700℃;

[0039] Ga 1-y In y P cell (or (AlGa) 1-x In x As cells), including n-type doped n-Ga 1-y In y P(or n-(AlGa) 1- x In x As) emitter layer and p-type doped p-Ga 1-y In y P (or p-(AlGa) 1-x In x As) base layer, wherein 0.4≤y≤0.9; wherein the n-Ga 1-y In y P(or n-(AlGa) 1-x In x As) The dopant of the emitter layer is Si, Se or Te, and the doping concentration is 1×10 17 -1×10 19 cm -3 , with a thickness range of 2-200nm and a growth temperature of 600–800°C; the p-Ga 1-y In y P (or p-(AlGa) 1-x In x As) The base layer is doped with Zn, Mg or C, with a doping concentration of 1×10 16 -1×10 18 cm -3 , thickness range is 100-2000nm, growth temperature is 600–800℃;

[0040] The fourth tunnel junction includes an n-type doped n + -(Al f Ga 1-f ) 1-y In y P layer and p-type doped p + -(Al i Ga1-i ) 1- x In x As layer, wherein the n + -(Al f Ga 1-f ) 1-y In y The dopant of the P layer is Si, Se or Te, and the doping concentration is 1×10 19 -1×10 21 cm -3 , 0.1≤f≤0.6 and 0.4≤y≤0.9, the thickness range is 1-100nm, and the growth temperature is 500–700℃; the p + -(Al i Ga 1-i ) 1-x In x The dopant of the As layer is Zn, Mg or C, and the doping concentration is 1×10 19 -1×10 21 cm -3 , 0.3≤i≤0.8 and 0.01≤x≤0.5, thickness range 1-100nm, growth temperature 500–700℃;

[0041] (Al f Ga 1-f ) 1-y In y P cells, including n-type doped n-(Al f Ga 1-f ) 1-y In y P emitter layer and p-type doped p-(Al f Ga 1-f ) 1-y In y P base layer, wherein 0.1≤f≤0.6 and 0.4≤y≤0.9; wherein the n-(Al f Ga 1-f ) 1-y In y The dopant of the P emitter layer is Si, Se or Te, and the doping concentration is 1×10 17 -1×10 19 cm -3 , with a thickness range of 2-200nm and a growth temperature of 600–800°C; the p-(Al f Ga 1-f ) 1-y In y The dopant of the P base layer is Zn, Mg or C, and the doping concentration is 1×10 16 -1×10 18cm -3 , thickness range is 100-2000nm, growth temperature is 600–800℃;

[0042] The cap layer is n-type doped + -Ga 1-x In x As, where 0.01≤x≤0.5, the dopant is Si, Se or Te, and the doping concentration is 1×10 18 -1×10 21 cm -3 , thickness range is 10-1000nm, and growth temperature is 500–800℃.

[0043] After the growth of the above-mentioned layers of materials, the total time is 3-9 hours, and the subsequent device process is exactly the same as that of the forward-matched triple-junction solar cell, which is a well-known technology.

[0044] The lattice-mismatched five-junction quantum well solar cell prepared by the present invention has a band gap of 2.0 / 1.7 / 1.4 / 1.1 (quantum well) / 0.7 (eV), a theoretical efficiency of 56.2%, a smaller lattice mismatch (higher open circuit voltage), and at the same time, due to the introduction of the quantum well structure, the short-circuit current will not decrease, and the theoretical efficiency is higher.

[0045] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A forward lattice mismatched five-junction quantum well solar cell, characterized in that: Including germanium substrate, from bottom to top, Ga 0.5 In 0.5 P nucleation layer, Ga 0.99 In 0.01 As buffer layer, first tunnel junction, lattice gradient buffer layer (Al c Ga 1-c ) 1-b In b As / (Al d Ga 1-d ) 1-b In b As DBR, Ga containing quantum well structure 1-x In x As battery, second tunnel junction, (Al c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As DBR, (Al e Ga 1-e ) 1-x In x As battery or Ga 1-x In x AsP battery, third tunnel junction, Ga 1-y In y P cell or (AlGa) 1-x In x As battery, fourth tunnel junction, (Al f Ga 1-f ) 1-y In y P cell and cap layer.

2. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The lattice gradient buffer layer (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 0.01≤b≤0.5, the component b of In gradually changes from 0.01 to x from bottom to top, using p-type dopant with a doping concentration of 1×10 17 -1×10 19 cm -3 , the thickness ranges from 1000-8000nm, the number of periods ranges from 10-40, and within each period, (Al c Ga 1-c ) 1-b In b The thickness of As is in the range of 20-200 nm, (Al d Ga 1-d ) 1-b In b The thickness of As ranges from 20 to 200 nm.

3. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The Ga containing quantum well structure 1-x In x As cells include n-type doped n-Ga 1-x In x As or n-Ga 1-y In y P emitter layer, Ga 1-r In r As / Ga 1-z In z As quantum well and p-type doped p-Ga 1-x In x As base layer, wherein 0.01≤x≤0.5, 0.01≤r≤0.4 and 0.01≤z≤0.6; wherein the n-Ga 1-x In x As or n-Ga 1-y In y The doping concentration of the P emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 20 to 200 nm; the p-Ga 1-x In x The doping concentration of the As base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 300-3000nm.

4. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The c Ga 1-c ) 1-x In x As / (Al d Ga 1-d ) 1-x In x As DBR, where 0≤c≤0.5, 0.5≤d≤1 and 0.01≤x≤0.5, uses p-type dopant with a doping concentration of 1×10 17 -1×10 19 cm -3 , the thickness ranges from 1000-4000nm, the number of periods ranges from 3-30, and within each period, (Al c Ga 1-c ) 1-x In x The thickness of As is in the range of 10-100 nm, (Al d Ga 1-d ) 1-x In x The thickness of As is in the range of 10-100 nm.

5. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The e Ga 1-e ) 1-x In x As battery or Ga 1-x In x AsP cells include n-type doped n-(Al e Ga 1-e ) 1-x In x As or n-Ga 1- x In x AsP emitter layer and p-type doped p-(Al e Ga 1-e ) 1-x In x As or p-Ga 1-x In x AsP base layer, wherein 0.1≤e≤0.6 and 0.01≤x≤0.5; wherein the n-(Al e Ga 1-e ) 1-x In x As or n-Ga 1-x In x The doping concentration of the AsP emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 20 to 200 nm; the p-(Al e Ga 1-e ) 1-x In x As or p-Ga 1-x In x The doping concentration of the AsP base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 300-3000nm.

6. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The Ga 1-y In y P cell or (AlGa) 1-x In x As cells include n-type doped n-Ga 1-y In y P or n-(AlGa) 1-x In x As emitter layer and p-type doped p-Ga 1-y In y P or p-(AlGa) 1-x In x As base layer, wherein 0.4≤y≤0.9; wherein the n-Ga 1-y In y P or n-(AlGa) 1-x In x The doping concentration of the As emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 2 to 200 nm; the p-Ga 1-y In y P or p-(AlGa) 1-x In x The doping concentration of the As base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 100-2000nm.

7. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The f Ga 1-f ) 1-y In y The P cell includes n-type doped n-(Al f Ga 1-f ) 1-y In y P emitter layer and p-type doped p-(Al f Ga 1-f ) 1-y In y P base layer, wherein 0.1≤f≤0.6 and 0.4≤y≤0.9; wherein the n-(Al f Ga 1-f ) 1-y In y The doping concentration of the P emitter layer is 1×10 17 -1×10 19 cm -3 , with a thickness ranging from 2 to 200 nm; the p-(Al f Ga 1-f ) 1-y In y The doping concentration of the P base layer is 1×10 16 -1×10 18 cm -3 , thickness range is 100-2000nm.

8. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The first tunnel junction includes an n-type doped n + -GaAs layer and p-type doped p + -Al g Ga 1-g As layer; wherein said n + The doping concentration of the GaAs layer is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -Al g Ga 1-g The doping concentration of the As layer is 1×10 19 -1×10 21 cm -3 , 0.1≤g≤0.6, thickness range is 1-100nm; The second tunnel junction includes an n-type doped n + -Ga 1-y In y P layer and p-type doped p + -(Al e Ga 1-e ) 1-x In x As layer, wherein the n + -Ga 1-y In y P layer, 0.4≤y≤0.9, doping concentration is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -(Al e Ga 1-e ) 1-x In x As layer, 0.1≤e≤0.6 and 0.01≤x≤0.5, doping concentration is 1×10 19 -1×10 21 cm -3 , thickness range is 1-100nm; The third tunnel junction includes an n-type doped n + -Ga 1-y In y P layer and p-type doped p + -(Al h Ga 1-h ) 1-x In x As layer, wherein the n + -Ga 1-y In y P layer, 0.4≤y≤0.9, doping concentration is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -(Al h Ga 1-h ) 1-x In x As layer, 0.2≤h≤0.7 and 0.01≤x≤0.5, doping concentration is 1×10 19 -1×10 21 cm -3 , thickness range is 1-100nm; The fourth tunnel junction includes an n-type doped n + -(Al f Ga 1-f ) 1-y In y P layer and p-type doped p + -(Al i Ga 1-i ) 1- x In x As layer, wherein the n + -(Al f Ga 1-f ) 1-y In y P layer, 0.1≤f≤0.6 and 0.4≤y≤0.9, doping concentration is 1×10 19 -1×10 21 cm -3 , the thickness range is 1-100nm; the p + -(Al i Ga 1-i ) 1-x In x As layer, 0.3≤i≤0.8 and 0.01≤x≤0.5, doping concentration is 1×10 19 -1×10 21 cm -3 , thickness range is 1-100nm.

9. The forward lattice mismatched five-junction quantum well solar cell according to claim 1, characterized in that: The cap layer is n-type doped + -Ga 1-x In x As, where 0.01≤x≤0.5, the doping concentration is 1×10 18 -1×10 21 cm -3 , thickness range is 10-1000nm.

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