Towards high efficiency multi-junction solar cells grown on InP Substrates

Progress toward the development of multi-junction solar cells grown on InP substrates is presented. In this material system, the optimal bandgaps for solar energy conversion are attained while the multi-junction structure is realized under lattice matched conditions. In this work, results for the characterization of material and devices of the individual sub cells are shown. For the top cell, InAlAsSb quaternary material is being developed. For the middle, InGaAsP and InGaAlAs are studied, and for the bottom, InGaAs will provide the possibility of adding multiple quantum wells for fine bandgap tunability. In addition, we will discuss electrical characterization of the tunnel diodes.