Fabrication and characterization of single junction GaAs solar cell epitaxially grown on Si substrate

•We report epitaxially grown GaAs single junction solar cell on Si substrate.•Performance of GaAs SC on Si was analyzed by optical and electrical characteristics.•We clarified defect states near the band edge strongly impact on performance of SC.

In this paper, we present GaAs solar cells on Si substrate by direct epitaxial growth of III–V layers on Si substrate. Fabricated solar cells have shown relatively high energy conversion efficiency of 11.17% without anti reflection coating. By analyzing external quantum efficiency, dark I–V characteristics, and photo luminescence spectra, we have found that possible defect state near the band edge strongly impact on the performance of GaAs solar cell on Si and termination of these defects will further improve the performance of GaAs solar cell directly grown on Si substrates.