High efficiency quadruple junction solar cells

Abstract This work focuses on the modeling and optimization of a structure based on InGaP/InGaAs/InGaAsN/Ge for photovoltaic. In this study we took into consideration the concentration effect of alloys x (In) and y (N) on the strain, the bandgap, the absorption and structure efficiency. It has been shown that the concentration of indium varies the strain and the bandgap. These two parameters change considerably the yield. Also it optimized the effect of alloys on the total absorption of the structure. For a concentration of indium x = 0.40 and y = 0.03 we had a absorption coefficient which is equal to 2 × 10 6  cm −1 . We have found 50% efficiency for the multi-junction structure based on In 0.55 Ga 0.45 P/In 0.40 Ga 0.60 As/In 0.30 Ga 0.70 As 0.97 N 0.03 /Ge. To achieve a reliable high efficiency multi-junction structure, we just need to optimize the concentrations of different alloys.