InGaP/GaAs/InGaAsP triple junction solar cells grown using solid-source molecular beam epitaxy

We report mechanically stacked InGaP (1.9 eV)/GaAs (1.42 eV)/InGaAsP (1.0 eV) triple junction solar cells fabricated with an advanced bonding technique using Pd nanoparticle arrays. High quality InGaP/GaAs tandem top and InGaAsP bottom cells are grown on GaAs and InP substrates, respectively using solid-source molecular beam epitaxy (MBE). The InGaAsP bottom cell has an open circuit voltage (Voc) of 0.49 V, which indicates that high performance InGaAsP solar cells can be fabricated using solid-source MBE. A fabricated triple junction solar cell has a high efficiency of 25.6% with a high Voc of 2.66 V.