High Efficiency GaAs/Ge Monolithic Tandem Cells for Space Concentrator Arrays.Phase 1

摘要

The goal of this program is to develop a 30 percent efficient 2-junction solarcell that is monolithic, two terminal, and that will operate in 25-100x solar concentrator elements with operating temperatures of 75-100 deg C. The cell design is a GaAs/Ge compound configuration with the Ge bottom cell utilizing the .9-1.8 micrometer portion of the AM0 solar spectrum and contributing 7 percent to the total stack efficiency. During the first Phase of this effort individual component cells were developed that had efficiencies of 22% for Gallium Arsenide and 6% for Germanium. Monolithically grown 2-junction devices were also fabricated with efficiencies exceeding 20% when characterized at the defined operating temperatures and solar concentration. (Author)