LAUSR

Abstract We report improved efficiency of GaInP solar cells by broadband omnidirectional antireflection owing to dielectric composite nanostructures. The dielectric composite nanostructures consisted of a nanopatterned SiO 2 layer and its underlying thin films composed of SiO 2 and SiN x dielectric layers. The GaInP solar cells decorated with these dielectric composite nanostructures exhibited significant antireflection for wavelengths in the 285–700 nm range, for incidence angles up to 60°, compared with those of bare cells and cells with a single antireflection layer (SARL). Accordingly, the photovoltaic performance of our solar cells was significantly better. Short circuit current density (J sc ) of 13.28 mA/cm 2 and fill factor (FF) of 85.47% were obtained at AM 1.5 G for these cells. The short circuit current density was 1.43 and 1.05 times higher than those for the bare cells and for the cells with a SARL, respectively. In the meantime, the fill factor was higher by 12% compared with that for the bare cells, although the improvement relative to the cells with a SARL was only marginal. Further investigation has indicated that these dielectric composite nanostructures effectively suppressed the dark saturation current and their surface passivation effect was stronger than that exhibited by the SARL-decorated GaInP solar cells, for the applied voltage below 1.34 V. As a result, conversion efficiency of 15.10% was achieved, which was 5.91% and 1.05% higher than those for the bare and SARL-decorated cells, respectively. Further analysis of the photovoltaic performance of the cells suggested that the improved performance can be attributed to the specific surface treatment, implying that these dielectric composite nanostructures can be truly employed in GaInP solar cells to enhance the conversion efficiency of these cells.