Ultrathin GaAs Solar Cells With a Silver Back Mirror

作者：Vandamme Nicolas^*; Chen Hung Ling; Gaucher Alexandre; Behaghel Benoit; Lemaitre Aristide; Cattoni Andrea; Dupuis Christophe; Bardou Nathalie; Guillemoles Jean Francois; Collin Stephane

来源：IEEE Journal of Photovoltaics, 2015, 5(2): 565-570.

DOI：10.1109/JPHOTOV.2014.2371236

• GaAs
• light-trapping
• thin film

We report on the fabrication and characterization of ultrathin GaAs solar cells with a silver back mirror and absorber thicknesses of only t = 120 nm and t = 220 nm. The silver back mirror is combined with localized ohmic contacts. Without antireflection coating, Fabry-Perot resonances lead to strong enhancement over single-pass absorption (up to 4), and external quantum efficiency reaches 0.8 at resonance wavelengths. An analytical model is used to determine the resonance wavelengths and the absorption maxima. Ashort-circuit improvement of 27% results from the enhanced absorption induced by the Fabry-Perot resonances. By implementing an additional antireflection coating, short-circuit currents reach 16.3 mA/cm(2) for t = 120 nm and 20.7 mA/cm(2) for t = 220 nm, corresponding to efficiencies of 8.7 % and 12.9 %, respectively.

• 出版日期2015-3