CARRIER RECOMBINATION OF GERMANIUM BACK-CONTACT TYPE BOTTOM CELLS FOR THREE-TERMINAL TANDEM SOLAR CELLS

摘要

In hope of resolving Ge cell current incompatibility, we have designed a new 3-terminal GaInP/GaAs/Ge triple-junction solar cell, incorporating a Ge back-contact type bottom cell. To obtain high efficiency of Ge back-contact type cell, which is greatly influenced by surface defect density, we studied the relation between diffusion layers and carrier transport characteristics, using device simulators. The study has clarified that this new solar cell can provide higher efficiency, resulting from reduced carrier recombination loss, enabled by diffused layer and hetero junction at the Ge front interface, and larger diffused region area at the back surface.