Method for preparing double-faced growth efficient wide-spectrum absorption multi-junction solar cell

Abstract

The invention discloses a method for preparing a double-faced growth efficient wide-spectrum absorption multi-junction solar cell. Indium phosphide (InP) extension on a gallium arsenide (GaAs) material and monolithic integration of GaAs and InP cells are realized by using a high depth-to-width ratio dislocation capture technology. The method specifically comprises the following steps of: (1) forming a medium film on a first face of a double-faced polished GaAs substrate, and growing a lattice-matched GaAs / GaInP solar cell structure on a second face of the GaAs substrate; (2) protecting the second face of the substrate, and processing nanoscale medium mask patterns on the first face of the substrate; (3) growing an InP thin film on the first face of the substrate, and polishing the InP thin film until the flatness reaches an extension level; (4) sequentially growing an InGaAsP or InGaAsP / InGaAs solar cell structure and an electrode contact layer on the first face of the substrate; and (5) unprotecting the second face of the substrate, and thus obtaining a target product. The method is simple in process, easy to operate and high in yield, and the influence of lattice mismatch and thermal mismatch in a heterogeneous multi-junction solar cell on the quality and performance of a cell material is effectively eliminated.

Description

technical field [0001] The invention relates to a preparation method of a photovoltaic device, in particular to a preparation method of a double-sided growth high-efficiency broad-spectrum absorption solar cell. Background technique [0002] As a typical way of utilizing solar energy, solar cells have become an important development direction of renewable energy. Improving the efficiency of solar cells is one of the goals pursued by solar cells. III-V group compound semiconductors are ideal for solar cell materials due to their broad energy band structure. GaAs-based III-V group multi-junction cells have been the efficiency record holders and creators in the field of solar cells since their inception. According to the solar spectrum and the band relationship of III-V materials, GaAs-based lattice-matched GaInP / GaAs double-junction cells and InP-based lattice-matched InGaAsP / InGaAs double-junction cells can be reasonably designed to cover most of the sun with current matching...

AI Technical Summary

Problems solved by technology

However, because the lattice mismatch between GaAs material and InP material reaches 3.8%, it is difficult to epitaxially high-quality InP material on GaAs by traditional methods. method to try to realize the quadruple-junction current-matched broad-spectrum absorption cell, however, on the one hand, wafer bonding involves a variety of processes (including layer transfer and chip lift-off technology), which reduces the success rate of the chip; on the other hand, GaAs materials and InP The direct bonding of materials has very high requirements on the cleanliness of the environment and equipment, and due to the difference in thermal expansion coefficient between the two, if the temperature difference in the post-bonding process or post-work is large, it will cause the warping of the material chip, and the two If the series resistance between the two is relatively large, it will virtually increase the electrical loss of the four-junction battery; if metal bonding is used, it will encounter the problem of balancing the series resistance and infrared optical absorption

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