REPRODUCIBLE INTEGRATION OF MULTIJUNCTION CASCADE CELL COMPONENTS

Efficient two-junction monolithic cascade solar cells (AlGaAs/GaInAs and AlGaAs/GaAs) were grown by metal-organic chemical vapor deposition (MOCVD) in two-terminal and three-terminal configurations. Owing to the complexity of the structures, the reproducible attainment of good efficiencies depends on the compatibility of the growth and/or processing conditions of the components, including the subcells, compositionally graded layers and subcell electrical interconnection. Recent modifications of the MOCVD deposition conditions have been found to favor such compatibility and hence permit the fabrication of efficient cascades. Both metal-interconnect technology and tunnel-junction technology have been successful.