[20a-B12-1~8] 13.9 Compound solar cells

△ [20a-B12-7] Fabrication and characterization of InGaAs/GaAs/GaAsP Wire on Well structure for high efficiency Ge-based multijunction solar cell

〇(M2)Meita Asami¹, Kentaroh Watanabe², Yoshiaki Nakano¹, Yoshitaka Okada^1,2, Masakazu Sugiyama^1,2 (1.The Univ. of Tokyo, 2.RCAST)

Keywords:solar cell, quantum well, multijunction

In recent years, the energy conversion efficiency of multijunction solar cells has reached over 40% and still in progress. Wire on Well (WoW) structure has been considered for a bandgap adjustor of multijunction solar cells and the carrier collection efficiency of a single-junction solar cell containing WoW is higher than that of a cell containing planar superlattice (PSL). However it was not clarified that which structure is able to achieve high energy conversion efficiency because there is a trade-off relationship between light absorption and carrier collection efficiency. This work provides direct evidence for the superiority of WoW over PSL in terms of the current density. Current density and optimum thickness of WoW structure were calculated measuring effective mobility and light absorption coefficient. It was revealed that the current density might increase by 1.4 mA/cm^-2 by applying WoW, and the optimum thickness is 0.72 μm.