[22a-A307-1~7] 13.9 Compound solar cells

▼ [22a-A307-2] Characterization of III-V Compound Triple Junction Solar Cells using Laser Beam Induced Current Mapping

〇(M2)Thakur Vaishnavi^1,2, Bernice Y. Espaldon³, Naoya Miyashita², Nazmul Ahsan², Yoshitaka Okada^1,2 (1.Eng. UTokyo, 2.RCAST, UTokyo, 3.NIMS)

Keywords:Luminescent Coupling, Inverted Metamorphic, LBIC

One of the strategies to improve the efficiency of multi-junction solar cells (MJSCs) is optimizing the internal luminescence that leads to photon generation. Due to the radiative recombination in higher bandgap sub-cells, the Luminescent Coupling(LC) effect results in the generation of extra photocurrent in the lower bandgap subcells of MJSCs. The role of the luminescent coupling effect in inverted metamorphic MJSC is analyzed and compared by characterizing a commercially available lattice-matched InGaP/ GaAs/Ge(LM-3J) and an InGaP/GaAs/InGaAs(IMM-3J) solar cell using Laser Beam Induced Current (LBIC) mapping method. From the LBIC mappings of the current distribution, it was observed that the LC and direct excitation are absorbed in a thin InGaAs direct bandgap bottom cell in IMM as opposed to a thick Ge indirect bandgap substrate-based bottom cell in LM. The LC photocurrent generation in the InGaAs bottom cell of IMM-3J is also higher than that of the Ge bottom cell of the LM-3J sample.