Device structure engineering of GaInNAsSb/GaAs heterojunction solar cells

The device structures of GaInNAsSb/GaAs based heteroj unction solar cells were studied. We fabricated a single-heterostructure (SH) and two double-heterostructures (DH) to investigate the carrier collection at the GaInNAsSb/GaAs hetero interface. The quantum efficiency at long wavelength region (λ > 870 nm) which is contributed from the GaInNAsSb layer shows higher values for DH structures than SH sample. On the other hand, the open circuit voltage of SH sample is higher than those of DH samples. This can be ascribed to an increased recombination current at the potential barrier (i/n interface) existing in DH structures.