Germanium multi-junction solar cell and preparation method thereof

Abstract

The invention discloses a germanium multi-junction solar cell and a manufacturing method thereof. The germanium multi-junction solar cell comprises a Ge sub-cell, an InGaAs sub-cell, an InGaAsP sub-cell and an InAlGaP sub-cell which are sequentially arranged in a stacked mode. According to the germanium multi-junction solar cell and the manufacturing method thereof disclosed by the invention, the manufacturing cost of the germanium multi-junction solar cell can be reduced, the photoelectric conversion efficiency of the germanium multi-junction solar cell can be improved, and the thin film and flexibility of the germanium multi-junction solar cell can be realized.

Description

technical field [0001] The invention belongs to the field of solar cells, and in particular relates to a germanium multi-junction solar cell and a preparation method thereof. Background technique [0002] Germanium multijunction solar cells have attracted more and more attention due to their high efficiency, high stability, high radiation resistance and many other advantages. However, the cost of germanium multi-junction solar cell products has always been high, and currently it is basically only used in the aerospace field. Existing germanium multi-junction solar cell products all use germanium substrates, and the germanium junctions are obtained by diffusing phosphorus on the germanium substrates, and then epitaxial to other multi-junction cell structures. However, the global reserves of germanium are only about 8,600 metal tons, and the global reserves of gold are also 86,000 tons. Germanium is scarcer than gold in terms of reserves. Therefore, the cost of the substrate...

AI Technical Summary

Problems solved by technology

Although the conversion efficiency of the four-junction battery will be improved compared with the three-junction battery design, the low mobility of the InGaNAs material itself will restrict the IQE to reach more than 95%, so the conversion efficiency is difficult to significantly improve

At the same time, the cost of GaAs substrate used for epitaxy is also high

[0009] In the patent number CN108054231A, a four-junction solar cell based on a Si substrate is described, which is a four-junction solar cell that realizes InGaP / GaAs / InGaAs / Si epitaxially on a Si substrate. This four-junction cell is not an optimal bandgap combination , the efficiency will be improved compared to the three-junction battery, but lower than the four-junction battery with the best band gap combination

Moreover, the epitaxial layer is thick, and no flexible substrate is used, so it is impossible to realize the flexible thin film of germanium four-junction cells.

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