Study on 2.05 eV Al0.13GaInP sub-cell and its hetero-structure cells

5-junction solar cells with 2.05 eV top sub-cells are the most promising structure to achieve the conversion efficiencies beyond 36% (AM0, 25°C). Al0.13GaInP (Eg≈ 2.05eV) sub-cell is grown by metal organic vapor-phase epitaxy (MOPVE), presenting an efficiency of 10.04% with 1457.3 mV in Voc and 11.9 mA/cm2 in Isc (AM0, 25°C). External quantum efficiency (EQE) of the sub-cell reveals the poor AlInP/Al0.13GaInP interface passivation, therefore the Isc of the sub-cell is limited. GaInP/Al0.13GaInP het-ero-structure is employed to improve the IV characteristics, especially the Isc, by enhancing the spectral response of the long-wavelength region, and further to improve the overall Isc of the 5-junction solar cell. Preliminary GaInP/Al0.13GaInP sub-cell shows en-hanced efficiency of 10.16%, with the Isc increased to 12.6 mA/cm2 and the Voc decreased to 1398.12 mV.