Multi-junction Iii-v Solar Cell And Manufacturing Method Thereof

Abstract

The invention relates to a multi-junction III-V solar cell and a manufacturing method thereof. The multi-junction solar cell structure includes a top photovoltaic cell including III-V semiconductor materials and a silicon-based bottom photovoltaic cell. A thin, germanium-rich silicon germanium buffer layer is provided between the top and bottom cells. Fabrication techniques for producing multi junction III-V solar cell structures, lattice-matched or pseudomorphic to germanium, on silicon substrates is further provided wherein silicon serves as the bottom cell. The open circuit voltage of the silicon cell may be enhanced by localized back surface field structures, localized back contacts, or amorphous silicon-based heterojunction back contacts.

Description

technical field [0001] The present disclosure relates to the physical sciences, and more particularly, to photovoltaic structures including III-V absorber materials and the fabrication of such structures. Background technique [0002] Due to germanium (Ge) and some III-V semiconductor materials such as InGaAs (In content is one percent (1%)) and InGaP 2 ), multijunction III–V solar cell structures are usually grown on Ge substrates. Therefore, due to its compatibility with InGaAs and InGaP 2 The Ge substrate also serves as the third junction in this structure compared to the smaller bandgap. Although using Ge as the bottom cell tends to increase the overall efficiency of conventional triple-junction solar cell structures, such solar cell structures are not optimal from a bandgap engineering perspective to maximize short-circuit current. To alleviate this problem, the use of upright metamorphic structures has been proposed, in which the bandgap of the intermediate InGaAs e...

AI Technical Summary

Problems solved by technology

However, inverted metamorphic solar cells are costly due to the special growth process to achieve a III-V junction with a band gap of ∼1.0 eV and the additional fabrication process required to separate the solar cell structure from the host substrate.

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