High-efficiency Al0.3Ga0.7As solar cells grown by molecular beam epitaxy

Abstract
This letter reports the growth of high‐efficiency Al0.3Ga0.7As solar cells by molecular beam epitaxy. As the growth temperature increases from 650 to 750 °C, the concentration of midgap electron traps in the active layers decreases from 4×1015 to less than 3×1013 cm3 and the hole diffusion length in the layers improves from 2.0 to 2.6 μm. For cells grown at 750 °C, an efficiency of 14.6% (AM1.5, 100 mW/cm2 for an active area) is obtained.