Additional efficiency enhanced for DL-ARC triple-junction GaAs/Ge solar cells based on indium nanoparticles surface plasmon light scattering

In this paper, we experimentally demonstrated the photovoltaic performance enhancement of a double layer (DL) anti-reflective coating (ARC) triple-junction GaAs/Ge solar cells by using indium nanoparticles surface plasmonics light scattering. The epitaxial structure of triple-junction GaAs/Ge solar cell was grown by metal-organic chemical vapor deposition (MOCVD) and the cell was deposited with TiO₂ and Al₂O₃ anti-reflective layers by e-beam evaporator on the top surface. A 3-nm thick indium lm was then deposited on ARC-layer surface by e-beam evaporation system and subsequently annealed by RTA at 200°C for 20 min in H₂ ambient to obtain nano-size indium nanoparticles. The performances of the fabricated DL-ARC triple-junction GaAs/Ge solar cell without indium nanoparticles show that the short circuit current (I_SC) of 12.46 mA, open circuit voltage (V _OC) of 2.53 V, fill factor (FF) of 0.87, and conversion efficiency (η) of 32.59% are obtained under 1 sun AM1.5G solar simulation. As the cell coated with indium nanoparticles, however, I_SC increase to 12.59mA and ́ increase to 33.18% are presented. The increase in I_SC and η are attributed to the contribution from the indium nanoparticles surface plasmonics light scattering. Additional efficiency of 1.79% enhanced for a DL-ARC triple-junction GaAs/Ge solar cell was obtained in this study.