Advanced Solar Cells for Satellite Applications

MicroLink Devices fabricates inverted metamorphic triple junction solar cells that are removed from their growth substrate by epitaxial lift-off, making them ultrathin, flexible, and extremely efficient (30% production level at AM0 solar spectra). These cells are currently sold to customers fabricating high-altitude long-endurance UAVs. MicroLink plans to expand its portfolio by fabricating space-qualified IMM solar cells. Changes in the solar cell structure, including thinner absorber layers and lower doping, are required for improved radiation tolerance. Layers that can reflect light back into a subcell will allow for thinner absorber layers. In this effort, MicroLink will fabricate a distributed Bragg reflector to reflect long wavelength light (800nm-875nm) back into the middle GaAs subcell, allowing its absorber layer to be thinned from >3 microns to ~1micron. The decreased thickness will improve the cell’s radiation tolerance dramatically.