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CN-121985591-A - Multi-junction solar cell and preparation method thereof

CN121985591ACN 121985591 ACN121985591 ACN 121985591ACN-121985591-A

Abstract

The application provides a multi-junction solar cell and a preparation method thereof, which relate to the technical field of solar cells, the multi-junction solar cell comprises a first junction sub-cell and at least one second junction sub-cell, wherein the first junction sub-cell comprises a Ge substrate, a nucleation layer and a composite functional buffer layer. The composite functional buffer layer comprises a first functional layer and a second functional layer, wherein the first functional layer is an InGaAs layer, the second functional layer is a GaAs layer or an AlGaAs layer, and x is more than 0 and less than or equal to 0.3. The lattice constant of the first functional layer in the multi-junction solar cell is between the lattice constants of Ge and GaAs/AlGaAs, the first functional layer can be used as a lattice transition layer between the Ge substrate and the upper composite functional buffer layer, and the first junction sub-cell has an optimized band gap combination, so that the first junction sub-cell can be well matched with the upper middle cell and the upper top cell in solar spectrum response.

Inventors

  • LIN ZHIWEI
  • WU ZHENLONG
  • HE JIAN
  • Tan Jiewei
  • ZHANG CE
  • CHEN YANGYU
  • Wen Zhongrui

Assignees

  • 扬州乾照光电有限公司
  • 江西乾照半导体科技有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (17)

  1. 1. A multi-junction solar cell, characterized in that the multi-junction solar cell comprises a first junction cell and at least one second junction cell; The first junction sub-battery comprises a Ge substrate, a nucleation layer and a composite functional buffer layer from bottom to top in sequence, wherein at least one second junction sub-battery is positioned on one side of the composite functional buffer layer far away from the nucleation layer, the composite functional buffer layer comprises a first functional layer and a second functional layer which are sequentially arranged along the direction far away from the nucleation layer, the first functional layer is an InGaAs layer, and the second functional layer is a GaAs layer or AlGaAs layer.
  2. 2. The multijunction solar cell of claim 1, wherein the first functional layer is an In x Ga 1-x As layer, 0< x≤0.3.
  3. 3. The multi-junction solar cell of claim 1 or 2, wherein the base layer of the first junction sub-cell comprises the Ge substrate, the emitter layer of the first junction sub-cell comprises the first functional layer, and the window layer of the first junction sub-cell comprises the second functional layer.
  4. 4. The multi-junction solar cell of claim 1, wherein the composite functional layer further comprises a transition layer between the first functional layer and the second functional layer; Wherein the transition layer is an InGaAs layer.
  5. 5. The multijunction solar cell of claim 4, wherein the transition layer is an In y Ga 1-y As layer, and the content y of In composition In the transition layer gradually decreases from x to 0 In a direction away from the first functional layer.
  6. 6. The multijunction solar cell of claim 4, wherein the first functional layer has a thickness D1, the second functional layer has a thickness D2, and the transition layer has a thickness D3, wherein D3< (d1+d2)/2.
  7. 7. The multi-junction solar cell of claim 1, wherein the thickness of the composite functional buffer layer ranges from 50nm to 1000nm inclusive, the thickness of the first functional layer ranges from 50nm to 900nm inclusive, and the thickness of the second functional layer ranges from 5nm to 200nm inclusive.
  8. 8. The multijunction solar cell of claim 1, wherein the Ge substrate is a P-doped monocrystalline Ge substrate having a carrier concentration in the range of 0.1/cm 3 ~5.0E18/cm 3 .
  9. 9. The multijunction solar cell of claim 8, wherein the composite functional buffer layer is an N-doped composite functional buffer layer, and the N-doped material of the composite functional buffer layer is Si.
  10. 10. The multijunction solar cell of claim 1, wherein the nucleation layer comprises one or more of a GaAs layer, an AlGaAs layer, an InAlGaAs layer, an AlGaInP layer, a INALGAASP layer, an AlGaAsP layer, a GaInP layer, or, The nucleation layer comprises a superlattice structure formed by one or more layers of a GaAs layer, an AlGaAs layer, an InAlGaAs layer, an AlGaInP layer, a INALGAASP layer, an AlGaAsP layer and a GaInP layer.
  11. 11. The multijunction solar cell of claim 1, wherein the nucleation layer has a thickness ranging from 2nm to 200nm inclusive and is less than the composite functional buffer layer.
  12. 12. The multi-junction solar cell of claim 1, wherein the at least one second junction cell comprises a GaAs cell and a GaInP cell in sequence in a direction away from the first junction cell.
  13. 13. A method of manufacturing a multi-junction solar cell, for manufacturing a multi-junction solar cell according to any one of claims 1-12, comprising: Providing a Ge substrate; sequentially forming a nucleation layer, a composite functional buffer layer and at least one second junction sub-cell on the Ge substrate, wherein the forming of the composite functional buffer layer comprises the following steps: and forming a first functional layer and a second functional layer in sequence along the direction far away from the nucleation layer, wherein the first functional layer is an InGaAs layer, and the second functional layer is a GaAs layer or an AlGaAs layer.
  14. 14. The method of claim 13, wherein the first functional layer is an In x Ga 1-x As layer, and the second functional layer is a GaAs layer or an AlGaAs layer, 0< x is less than or equal to 0.3.
  15. 15. The method of claim 13 or 14, wherein the base layer of the first junction sub-cell comprises the Ge substrate, the emitter layer of the first junction sub-cell comprises the first functional layer, and the window layer of the first junction sub-cell comprises the second functional layer.
  16. 16. The method of claim 13, wherein forming the composite functional layer further comprises: forming a transition layer after forming the first functional layer and before forming the second functional layer, the transition layer being located between the first functional layer and the second functional layer; Wherein the lattice transition layer is an InGaAs layer.
  17. 17. The method of claim 16, wherein the transition layer is an In y Ga 1-y As layer, and the content y of the In component In the transition layer gradually decreases to 0 In a direction away from the first functional layer.

Description

Multi-junction solar cell and preparation method thereof Technical Field The application relates to the technical field of solar cells, in particular to a multi-junction solar cell and a preparation method thereof. Background Gallium arsenide, which is a III-V compound semiconductor material, has a higher degree of matching between the energy gap and the solar spectrum, so that the degree of matching between the energy gap and the solar spectrum of a gallium arsenide solar cell is superior to that of a silicon solar cell. Therefore, the gallium arsenide solar cell can far exceed the silicon solar cell in theoretical efficiency, and the theoretical efficiency of the specific gallium arsenide solar cell is about twice that of the crystalline silicon solar cell, so that the sensitivity to sunlight is higher. And because the arsenide solar cell (such as a GaAs cell) has higher photoelectric conversion efficiency, excellent radiation resistance and high temperature resistance, the arsenide solar cell has an irreplaceable position in space spaceflight, concentrating photovoltaic (Concentrator Photovoltaics, CPV for short) and certain special ground application fields. Disclosure of Invention In view of the above, the application provides a multi-junction solar cell and a preparation method thereof, and the scheme is as follows: a multi-junction solar cell comprising a first junction cell and at least one second junction cell; The first junction sub-battery comprises a Ge substrate, a nucleation layer and a composite functional buffer layer from bottom to top in sequence, wherein at least one second junction sub-battery is positioned on one side of the composite functional buffer layer far away from the nucleation layer, the composite functional buffer layer comprises a first functional layer and a second functional layer which are sequentially arranged along the direction far away from the nucleation layer, the first functional layer is an InGaAs layer, and the second functional layer is a GaAs layer or AlGaAs layer. Optionally, the first functional layer is an In xGa1-x As layer, and 0< x is less than or equal to 0.3. Optionally, the base layer of the first junction sub-cell includes the Ge substrate, the emitter layer of the first junction sub-cell includes the first functional layer, and the window layer of the first junction sub-cell includes the second functional layer. Optionally, the composite functional layer further comprises a transition layer, the transition layer being located between the first functional layer and the second functional layer; Wherein the transition layer is an InGaAs layer. Optionally, the transition layer is an In yGa1-y As layer, and the content y of the In component In the transition layer gradually decreases from x to 0 along a direction away from the first functional layer. Optionally, the first functional layer has a thickness D1, the second functional layer has a thickness D2, and the transition layer has a thickness D3, wherein D3< (d1+d2)/2. Optionally, the thickness of the composite functional buffer layer is 50 nm-1000 nm, including the end point value, the thickness of the first functional layer is 50 nm-900 nm, including the end point value, and the thickness of the second functional layer is 5 nm-200 nm, including the end point value. Optionally, the Ge substrate is a P-type doped monocrystalline Ge substrate, and the carrier concentration of the Ge substrate is in a range of 0.1/cm 3~5.0E18/cm3. Optionally, the composite functional buffer layer is an N-type doped composite functional buffer layer, and the N-type doped material of the composite functional buffer layer is Si. Optionally, the nucleation layer comprises one or more of a GaAs layer, an AlGaAs layer, an InAlGaAs layer, an AlGaInP layer, a INALGAASP layer, an AlGaAsP layer, a GaInP layer, or, The nucleation layer comprises a superlattice structure formed by one or more layers of a GaAs layer, an AlGaAs layer, an InAlGaAs layer, an AlGaInP layer, a INALGAASP layer, an AlGaAsP layer and a GaInP layer. Optionally, the thickness of the nucleation layer ranges from 2nm to 200nm, including the end point value, and the thickness of the nucleation layer is smaller than the thickness of the composite functional buffer layer. Optionally, the at least one second junction sub-cell comprises a GaAs cell and a GaInP cell in sequence in a direction away from the first junction sub-cell. A method of fabricating a multi-junction solar cell for fabricating a multi-junction solar cell as claimed in any one of the preceding claims, the method of fabricating a multi-junction solar cell comprising: Providing a Ge substrate; sequentially forming a nucleation layer, a composite functional buffer layer and at least one second junction sub-cell on the Ge substrate, wherein the forming of the composite functional buffer layer comprises the following steps: and forming a first functional layer and a second functional layer in sequence a