Temperature-Induced Degradation of Thin-Film III–V Solar Cells for Space Applications

High-efficiency, thin-film III-V solar cells offer excellent characteristics for implementation in flexible solar panels for space applications. In order to investigate the space compatibility of such cells, the temperature-induced degradation of both substratebased cells with Au and Au/Cu contacts and thin-film cells on Au and Cu carriers was studied by accelerated ageing testing (AAT) at 200 °C. With less than a 3% decrease in efficiency after 37 days at 200 °C (equivalent to 10 years at 100 °C for E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> = 0.70 eV), the substrate-based cells show excellent results. With a 10% decrease in efficiency after 37 days of AAT, the thin-film cells on an Au carrier exhibit promising results, given the early stage of development of the thin-film cells. On the other hand, severe degradation is observed for thin-film cells on a Cu carrier (decrease in efficiency> 60% after 37 days of AAT). At least two factors contribute to this severe degradation: thermally induced stress and Cu diffusion.