The GaAs/GaAs/Si solar cell - Towards current matching in an integrated two terminal tandem

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• 作者：Zekun Ren^a ; Haohui Liu^b ; Zhe Liu^b ; Chuan Seng Tan^a ; ^d ; Armin G. Aberle^b ; Tonio Buonassisi^a ; ^c ; Ian Marius Peters^a ; ^c ; ^{impeters@mit.edu} ; ^{ian.marius.peters@gmail.com}
• 关键词：One sun tandem solar cell ; III-V on Si ; GaAs on Si
• 刊名：Solar Energy Materials and Solar Cells
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：160
• 期：Complete
• 页码：94-100
• 全文大小：602 K
• 卷排序：160

文摘

Non-concentrating tandem solar cells offer the potential to increase conversion efficiencies beyond 30%. Of particular interest are configurations with a silicon bottom cell – to leverage existing manufacturing infrastructure – and III-V compound semiconductor top cells to combine high efficiencies with long-term stability and experience in applications. In this work we investigate the GaAs/GaAs/Si triple-junction architecture. GaAs and Si form a non-ideal bandgap combination, which poses a challenge to the current matching requirement. As band-to-band absorption in GaAs is almost two thirds of that in Si, absorption can be balanced by replacing the GaAs top junction with a GaAs/GaAs double junction. This opens up a possibility for an integrated two terminal solar cell for the GaAs-Si material system. In this study, we numerically evaluate the efficiency and energy yield potential of the GaAs/GaAs/Si triple-junction architecture. We find that, with state-of-the-art material quality, the GaAs/GaAs/Si architecture has the potential to achieve 33.0% efficiency, and harvesting efficiencies between 31.4% and 32.1%. We fabricated a GaAs/GaAs/Si four-terminal tandem solar cell with a mathematically combined efficiency of 20.4%.