Flexible GaAs Single-Junction Solar Cells Based on Single-Crystal-Like Thin-Film Materials Directly Grown on Metal Tapes

We demonstrate flexible single-junction III-V solar cells based on single-crystal-like GaAs thin films directly grown on a metal tape. The epitaxial (Al)GaAs thin-film structures are developed on flexible polycrystalline Hastelloy tapes using crystallinity-transformational buffer layers for photovoltaic devices with front illumination geometry. The GaAs solar cell shows promising photovoltaic characteristics under AM 1.5G 1-Sun illumination. An open-circuit voltage of 330mV, a short circuit current of 21mA/cm
²
, and a fill factor of 73 result in a conversion efficiency of ~5%. Further improvement in semiconductor thin films quality, device design and fabrication process optimization would improve the device performance characteristics. This new technology has the potential for next-generation low-cost and high efficiency flexible photovoltaic devices.