Five junction laminated solar cell and manufacturing method therefor

Abstract

The invention relates to the technical field of a solar cell and provides a five junction laminated solar cell and a manufacturing method therefor. The five junction laminated solar cell comprises a three junction cell structure and a two junction cell structure; the three junction cell structure orderly comprises a GaAs cap layer, an AlGaInP sub-cell, a first tunnel junction, an AlGaAs sub-cell, a second tunnel junction, a GaAs sub-cell, a third tunnel junction and a first bonding layer; the two junction cell structure orderly comprises a Ge substrate, a window layer, a fourth tunnel junction, a (AlGa)yIn1-yAs crystal lattice gradual change buffer layer, a GaxIn1-xAs sub-cell and a second bonding layer; the three junction cell structure and the two junction cell structure are combined via bonding of the first bonding layer and the second bonding layer, a cell band gap structure is enabled to effectively match a solar spectrum, full play is given to advantages of an III-V laminated solar cell, open-circuit voltage and fill factors of the cell can be increased, and photoelectric conversion efficiency of the cell can be improved.

Description

technical field [0001] The invention belongs to the technical field of solar cells, in particular to a five-junction stacked solar cell and a preparation method thereof. Background technique [0002] Due to the advantages of high efficiency, long life and high reliability, III-V multi-junction solar cells are widely used in space power systems and terrestrial concentrated photovoltaic power generation systems. The most mature and widely used III-V multi-junction solar cell is the GaInP / Ga(In)As / Ge triple-junction solar cell, whose photoelectric conversion efficiency has reached 30% under the AM0 spectrum. In order to continue to improve the efficiency of solar cells to achieve efficient absorption and utilization of the solar spectrum, III-V solar cells are developing towards more junctions. Four-junction solar cell technology, its typical bandgap structure is 1.9 / 1.42 / 1.02 / 0.75eV, and the efficiency under AM0 spectrum can reach 33-34%. However, in order to further improve...

AI Technical Summary

Problems solved by technology

Among them, the method of using the dilute nitrogen compound GaInAsN as the material of the 1.0eV sub-cell is to grow GaInAsN (1.0eV) sub-cell, GaInAs (1.4eV) sub-cell, AlGaInAs ( 1.7eV) sub-cells and AlGaInP (2.05eV) sub-cells to form a laminated battery structure, but the crystal quality of the GaInAsN epitaxial material grown by the current technical means is poor, which makes the performance of the 1.0eV sub-cells low, resulting in the stacked battery overall inefficiency

The semiconductor bonding technology involves two preparation methods, one is to reversely grow AlGaInP (2.05eV) sub-cells, AlGaInAs (1.7eV) sub-cells, GaAs (1.42eV), GaInAs (1.0eV) on the GaAs substrate ) and GaInAs (0.75eV) subcells, and then bond them to a supporting substrate such as Si, and finally etch away the GaAs substrate to obtain a five-junction solar cell, but this method needs to grow two lattice-mismatched gradient buffer layers , first transition the lattice constant to 1.0eV GaInAs, and then transition to 0.7eV GaInAs, due to the large lattice mismatch between 0.7eV GaInAs and GaAs substrate, it is difficult to grow high-quality 0.7eV GaInAs sub-cells, and the bond The surface condition of the bonding interface is poor, which affects the bonding yield

The other is to grow AlGaInP (2.05eV) sub-cells, AlGaInAs (1.7eV) sub-cells and GaInAs (1.4eV) sub-cells on the GaAs substrate in reverse and grow GaInAs (0.75eV) on the InP substrate Sub-cells and GaInAsP (1.05eV) sub-cells, and then these two parts of sub-cells are bonded together to form a five-junction solar cell through a semiconductor bonding process, but the expensive InP substrate involved in this method will lead to high battery costs

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