Three-junction cascade solar cell and manufacturing method thereof

Abstract

The invention relates to the technical field of solar energy, in particular to a three-junction cascade solar cell and a manufacturing method thereof. The manufacturing method comprises the following steps that a GaAs1-x-yNxBiy bottom cell layer, a first tunnel junction, an InmGa1-mAs1-nNn intermediate cell layer, a second tunnel junction, an AlpGa1-p-qInqP top cell layer and a GaAs contact layer grow sequentially on a GaAs substrate through adoption of an organometallic chemical vapor deposition method; ohmic electrodes are manufactured at the bottom of the GaAs substrate and the top of the GaAs contact layer. The invention further provides a structure of the solar cell. According to the three-junction cascade solar cell and the manufacturing method, subsection absorption and utilization of solar spectra and current matching of cells are achieved, the cell layers are matched with GaAs lattices, high cell efficiency can be obtained, and the three-junction cascade solar cell is a potential and ideal solar cell material.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a structure of a triple-junction cascaded solar cell and a manufacturing method thereof. Background technique [0002] In the field of III-V solar cells, multi-junction systems are usually used to achieve segmental absorption and utilization of the solar spectrum to obtain higher conversion efficiency. GaInP / GaAs / Ge triple-junction cells are currently the most researched and technically mature system. The battery has achieved the highest conversion efficiency of 32-33%. However, there is still a major problem in this system that the Ge battery covers a wider spectrum, and its short-circuit current can reach twice that of the other two-junction batteries. Due to the constraints of the three-junction batteries connected in series, the energy of the solar spectrum corresponding to the Ge battery is not captured. Full conversion utilization. Calculations show that the conversi...

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Problems solved by technology

[0003] A material that can achieve this combination of gaps is AlInAs / InGaAsP / InGaAs, but the lattice constant of this material has a mismatch with the GaAs substrate by about 2.5%, and there is still no substrate that matches the lattice constant of the above materials.

In order to obtain AlInAs / InGaAsP / InGaAs materials with 1.93eV / 1.39eV / 0.94eV band-gap combination, a common method is to grow a lattice-variation buffer layer on a GaAs substrate by using lattice-variation technology to achieve a constant lattice constant. However, this technology puts forward higher requirements for material growth, and the introduction of the buffer layer also brings more defects, which reduces the performance of the battery

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