Analyses of Interfaces in Wafer-Bonded Tandem Solar Cells by Aberration-Corrected STEM and EELS

High-quality III-V multi junction solar cells on Si can be fabricated by surface-activated wafer bonding at room temperature. In this way the formation of lattice-mismatch induced defects in the active solar cell layers can be reduced or completely avoided. In this approach, a 10 μm thin GaInP/GaAs dual junction solar cell is grown lattice-matched on GaAs and transferred to Si by direct wafer bonding (Figure 2).