High Efficiency, Multijunction GaInP/GaAs Solar Cells

For most of the last two decades the energy conversion efficiency of monolithic, two-terminal, two-junction solar cells has steadily increased. The current leader in this field is the CaInP/GaAs tandem cell with an efficiency of 30%. In this paper, we briefly review the technology of tandem cells with an emphasis on the GaInP/GaAs device structure and its near-term potential for poweringcommunication satellites and far-term potential for large scale terrestrial concentrator applications. We then review key aspects of this device, focusing on some of the interesting problems that have been encountered over the years in the development of this device structure, e.g. spontaneous ordering of GaInP, hetrointerface quality, dopant diffusion/memory effects, and large scale productionefforts.