Antireflecting‐metal‐oxide‐semiconductor (AMOS) technology has been applied to sliced wafers of polycrystalline GaAs having grain sizes of about 100 &mgr;m. Simulated AM1 sunlight efficiencies up to 14% were obtained, and studies using the scanning electron microscope showed that grain boundaries have minimal effect on short‐circuit current density. However, current‐voltage characteristics show some influence on open‐circuit voltage.