键合集成AlGaInP/GaAs/InGaAsP/InGaAs太阳电池组分与厚度对效率的影响

Effect of composition and cell thickness on efficiency of direct bonded AlGaInP/GaAs/InGaAsP/InGaAs solar cell

寻找比传统晶格匹配GaInP/InGaAs/Ge结构具有很高效率的高效太阳电池体系是目前高效太阳电池研究重点。基于直接键合集成技术的AlzGa1-zInP/GaAs/In1-xGaxAsyP1-y/InGaAs四结太阳电池是一条有效的途径。该结构中In-GaAsP材料光学带隙可以在0.75～1.35 eV之间连续调节。作为一种新结构,一些关键点还是不清楚,比如考虑材料吸收系数与实际厚度限制下的带隙优化组合,子电池厚度与最高效率之间的耦合影响等,这些都对结构设计提出了新的挑战。采用半经验全局优化工具,研究了InGaAsP子电池组分和吸收系数比较小的InGaAs子电池厚度这两个因素对最高效率的影响,并对器件设计给出了一些方向性意见。

More and more attentions are paid to explore novel structures beyond the most successful lattice-matched GaInP/（In）GaAs/Ge triple junction solar cells,which reaches the pilot production of 30%（AM0）.For the device struc-tures with more than 3 junctions,the four junction AlzGa1-zInP/GaAs/In1-xGaxAsyP1-y/InGaAs structure based on wafer-bonding technology is a potential solution,which may reach 35% under AM0 illumination.The bandgap of the third subcell can be varied from 0.75 eV to 1.35 eV.However,some essential issues are still unclear,such as the optimal bandgap combination,the correlation between the maximum efficiency and the subcell thickness constraints,which is critical for the practical material growth.In other words,the optimal structure should have practically finite subcell thicknesses while achieving the possible high efficiency.In this paper,a material optical constant based glob-al optimization model for this structure was established and then these issues were clarified.