|Title||Towards Demonstration of GaAs0.76P0.24/ Si Dual Junction Step-Cell|
|Publication Type||Book Chapter|
|Year of Publication||2016|
|Authors||Hadi, SAbdul, Milakovich, T, Shah, R, Fitzgerald, EA, Nayfeh, A|
|Book Title||2016 Ieee 43rd Photovoltaic Specialists Conference (pvsc)|
|Pagination||1881 - 1886|
|Keywords||III-V semiconductor materials, layers, multi-junction, photovoltaic cells, silicon, silicon germanium, solar-cells|
Here we present an initial demonstration of a dual junction step-cell using single junction (SJ) GaAs0.76P0.24 cell, grown on Si1-yGey/Si substrates, as the top cell and Si as the bottom cell. To demonstrate step-cell, two SJ cells are connected in series, without removing SiGe/Si carrier from III-V cell, and illuminated Si cell area is varied. Measured efficiency of optimized demo step-cell under 1 sun and without anti-reflective coating on III-V cell is similar to 11.8%. Using SJ cells characterization and optical data, we estimate maximum efficiency of bonded 1 mu m GaAs0.76P0.24// 650-mu m Si step-cell to be similar to 26% at optimized total-to-top cell area ratio equal to 1.1. Results presented here show that step-cell can be used as added optimization design parameter for tandem cells.