Performance improvement of III–V compound solar cells using nanomesh electrode and nanostructured antireflection structures

To improve the conversion efficiency of InGaP/InGaAs/Ge triple-junction solar cells, AuGeNi/Au nanomesh electrode structure and TiO₂ nanostructured antireflection structure were designed and fabricated. Laser interference photolithography system was used to pattern 330-nm-wide nanomesh electrode structures with various AuGeNi/Au metal line intervals. Oblique evaporation method using electron beam evaporator was used to deposit TiO₂ nanorod arrays with various periods. By using the AuGeNi/Au nanomesh electrode structure with metal line interval of 100 μm, the conversion efficiency of the InGaP/InGaAs/Ge triple-junction solar cells was improved to 35.25% compared with 30.84% of that with conventional bus-bar electrode structure. By using the TiO₂ nanorod array with a period of 1.00 μm to replace the TiO₂/SiO₂ antireflection structure, the conversion efficiency was further improved from 35.25% to 37.00%.