A lattice-matched six-junction solar cell

Abstract

The invention discloses a lattice-matched six-junction solar cell. The cell uses a p-type Ge single wafer as a substrate, and a GaInAs / GaInP buffer layer, AlGaAs / GaInAs DBR, Ga1‑3xIn3xNxAs1‑are sequentially arranged on the Ge substrate x subcell, AlAs / AlGaAs DBR, Ga1‑3yIn3yNyAs1‑y subcell, GaInAs subcell, AlGaInAs subcell and AlGaInP subcell, where AlGaAs / GaInAs DBR is used to reflect long-wavelength photons, and AlAs / AlGaAs DBR is used to reflect medium- and long-wavelength photons . The invention can make the photon be absorbed and utilized by the sub-cell for the second time, improve the collection efficiency of the sub-cell, thereby improving the overall photoelectric conversion efficiency of the six-junction solar cell; at the same time, the invention can also reduce the thickness of the sub-cell and reduce the production cost of the battery.

Description

technical field [0001] The invention relates to the technical field of solar photovoltaics, in particular to a lattice-matched six-junction solar cell. Background technique [0002] At present, solar cells can be roughly divided into three categories from the perspective of technological development history: the first generation of crystalline silicon solar cells, the second generation of thin-film solar cells and the third generation of gallium arsenide concentrating (multi-junction) solar cells. Gallium arsenide multi-junction solar cells are widely used in concentrated photovoltaic (CPV) systems and space power systems because their conversion efficiency is significantly higher than that of crystalline silicon cells. The mainstream structure of gallium arsenide multi-junction solar cells is a GaInP / GaInAs / Ge triple-junction solar cell composed of GaInP, GaInAs and Ge sub-cells. The cell structure maintains lattice matching as a whole, and the band gap combination is 1.85 / ...

AI Technical Summary

Problems solved by technology

[0004] However, in the actual preparation process of GaInNAs materials, since GaInNAs needs to be grown at low temperature to ensure the effective incorporation of N atoms, a large number of C atoms will be introduced into the material at the same time, causing the background carrier concentration to be too high and affecting the minority carrier diffusion length.

At this time, if the GaInNAs material layer is too thick, the photo-generated carriers cannot be collected effectively; if the GaInNAs material layer is too thin, the battery absorption rate is too low, and the photons of the corresponding wavelength band cannot be completely absorbed.

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