Progress toward technology transition of GaInP2/GaAs/Ge multijunction solar cells

The objective of the joint WL/PL/NASA Multijunction Solar Cell Manufacturing Technology (ManTech) Program is to scale up high efficiency GaInP₂/GaAs/Ge multijunction solar cells to production size, quantity, and yield while limiting the production cost/Watt ($/W) to 15% over GaAs cells. Progress made by the program contractors, Spectrolab and TECSTAR, include, respectively, best cell efficiencies of 25.76% and 24.7% and establishment of 24.2% and 23.8% lot average efficiency baseline designs. The paper also presents side-by-side testing results collected by Phillips Laboratory and NASA Lewis on Phase I deliverable cells, which shows compliance with program objectives. Cell performance, pre- and post-radiation, and temperature coefficient results on initial production GaInP₂/GaAs/Ge solar cells are presented