Japanese Journal of Applied Physics · 2015 · 14 citations · 30 references
EngineeringElectrical EngineeringMaterials ScienceElectronic MaterialsOptoelectronicsSemiconductor MaterialsCompound SemiconductorsIii-v SemiconductorsPhotovoltaic DevicesSemiconductor HeterostructuresSemiconductor PhysicsSolar CellsHeterojunction Solar CellsHeterostructure Solar CellsMulti-junction Solar CellsOptical LossesPhotovoltaic SystemsSolar Cell FabricationThermal DamageWafer Bonding Of Heterogeneous Materials
We have developed III-V compound semiconductor multi-junction solar cells by a room-temperature wafer-bonding technique to avoid the formation of dislocations and voids due to lattice mismatch and thermal damage during a conventional high-temperature wafer-bonding process. First, we separately grew an (Al) GaAs top cell on a GaAs substrate and an InGaAs bottom cell on an InP substrate by metal solid source molecular beam epitaxy. Thereafter, we successfully bonded these sub-cells by the room-temperature wafer-bonding technique and fabricated (Al) GaAs parallel to InGaAs wafer-bonded solar cells. To the best of our knowledge, the obtained GaAs parallel to InGaAs and AlGaAs parallel to InGaAs wafer-bonded solar cells exhibited the lowest electrical and optical losses ever reported. The AlGaAs parallel to InGaAs solar cells reached the maximum efficiency of 27.7% at 120 suns. These results suggest that the room-temperature wafer-bonding technique has high potential for achieving higher conversion efficiencies. (C) 2015 The Japan Society of Applied Physics
30
40% efficient metamorphic GaInP∕GaInAs∕Ge multijunction solar cells
Richard R. King, D. C. Law, K. Edmondson et al. · Applied Physics Letters · 2007 · 1.2K citations · Full text