GaAsP/Si tandem solar cells: Realistic prediction of efficiency gain by applying strain-balanced multiple quantum wells
GaAsP/Si tandem solar cells: Realistic prediction of efficiency gain by applying strain-balanced multiple quantum wells
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DOI：
10.1016/j.solmat.2017.06.060
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发表时间：
2017-07
影响因子：
6.9
通讯作者：
Boram Kim;K. Toprasertpong;A. Paszuk;O. Supplie;Y. Nakano;T. Hannappel;M. Sugiyama
中科院分区：
文献类型：
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作者：
Boram Kim;K. Toprasertpong;A. Paszuk;O. Supplie;Y. Nakano;T. Hannappel;M. Sugiyama
可调直接带隙III-V族吸收体与有源Si衬底的组合有望实现高效串联太阳能电池。然而，为了产生1.6和1.8 eV之间的理想III-V带隙，这被认为是实现与Si底电池的电流匹配，迄今为止必须考虑大的晶格失配或稀氮化物。在这里，我们提出了一种新的结构的两端III-V-on-Si太阳能电池的基础上，应变平衡的III-V多量子威尔斯（MQW）嵌入在一个变质的GaAsP顶电池矩阵。应变平衡的多量子阱将吸收边扩展到更长的波长，并且能够减少GaAsP变质顶电池基质中的As含量。多量子阱中载流子的积累有利于辐射复合，有利于提高效率，而深量子威尔斯阱降低了载流子的收集效率。在这里，我们预测太阳能转换效率超过42.6%，整个MQW薄至500 nm。所应用的模型考虑了多量子阱的缺点，如有限的光吸收和限制的载流子收集的瓶颈。
The combination of tunable direct bandgap III-V absorbers with active Si substrates promises high-efficiency tandem solar cells. To yield the ideal III-V bandgaps between 1.6 and 1.8 eV which is considered to achieve current matching with the Si bottom-cell, however, either a big lattice-mismatch or dilute nitrides had to be considered so far. Here, we propose a new structure for a two-terminal III-V-on-Si solar cell which bases on strain-balanced III-V multi-quantum wells (MQWs) embedded in a metamorphic GaAsP top-cell matrix. Strain-balanced MQWs extend the absorption edge to a longer wavelength and enable a reduction of the As content in the GaAsP metamorphic top-cell matrix. And accumulation of carriers in MQWs favors radiative recombination, which is beneficial for high efficiency while deep quantum wells lower the charge carrier collection efficiency. Here, we predict solar energy conversion efficiencies over 42.6% with an entire MQW as thin as 500 nm. The applied model takes into account the drawbacks of MQWs, such as limited light absorption and the bottleneck of charge carrier collection from the confinement.