Improving GaInP/GaAs/Ge triple junction solar cell efficiency with reduced growth temperature of GaAs base layer

Abstract

Using GaInP as a nucleation layer, the Ge bottom cell was fabricated with a proper junction depth in the p-n junction and this Ge bottom cell was used to grow GaInP/GaAs/Ge triple junction solar cells. Then, the growth temperature of p-type GaAs base layer in the middle cell was investigated as a means of improving the solar cell efficiency. The solar cell grown at 550°C produced the improved efficiency compared to that grown at 680°C. The result suggests that the growth temperature of GaAs base layer is an important factor to improve the cell efficiency, related to the thermal stability of previously formed bottom cells.