Enhanced-depletion-width GaInNAs solar cells grown by molecular-beam epitaxy

GaInNAs, potentially useful in a 4-junction GaInP₂/GaAs/GaInNAs/Ge solar cell, suffers from very low minority-carrier collection lengths. To date, the currents available from GaInNAs solar cells are not high enough to increase the efficiency of a 3-junction device by adding this fourth junction. Here, we grow p-i-n GaInNAs solar cells by MBE with wide, intrinsic base layers and internal QE´s near 1.0. If similar 1.0-eV GaInNAs junctions can be successfully integrated into the 3-junction structure, the resulting 4-junction cell would have a higher efficiency.