35.8% Space And 38.8% Terrestrial 5j Direct Bonded Cells

Spectrolab has fabricated a direct semiconductor bonded space solar cell with an efficiency of 35.8% under the AM0 space spectrum. Using a similar technology, Spectrolab has achieved as-junction (5J) direct bonded terrestrial cell with a record efficiency of 38.8% under the one-sun AM1.5G terrestrial spectrum. Efforts to further improve the SJ cell efficiency have focused on development of the top 3 junctions (T3J) grown on GaAs. Experiments with top 3J isotype cells have yielded an improvement of 1 % in current and 100 mV in voltage for the T3J. Spectrolab has also made significant improvements in its direct bonding process. The improved process has increased bond strengths by more than a factor of 5 and eliminated issues with large voids.