Title :
Ultrathin GaAs Solar Cells With a Silver Back Mirror
Author :
Vandamme, Nicolas ; Chen Hung-Ling ; Gaucher, Alexandre ; Behaghel, Benoit ; Lemaitre, Aristide ; Cattoni, Andrea ; Dupuis, Christophe ; Bardou, Nathalie ; Guillemoles, Jean-Francois ; Collin, Stephane
Author_Institution :
Lab. de Photonique et de Nanostruct., Marcoussis, France
Abstract :
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. A short-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/cm2 fort = 120 nm and 20.7 mA/cm2 for t = 220 nm, corresponding to efficiencies of 8.7 % and 12.9 %, respectively.
Keywords :
III-V semiconductors; antireflection coatings; gallium arsenide; mirrors; ohmic contacts; semiconductor device models; silver; solar cells; Fabry-Perot resonances; GaAs-Ag; absorber thickness; absorption maxima; analytical model; antireflection coating; external quantum efficiency; localized ohmic contacts; resonance wavelengths; short-circuit currents; silver back mirror thickness; single-pass absorption; size 120 nm; size 220 nm; ultrathin GaAs solar cells; Absorption; Gallium arsenide; Mirrors; Ohmic contacts; Photovoltaic cells; Short-circuit currents; Silver; GaAs; light-trapping; thin film;
Journal_Title :
Photovoltaics, IEEE Journal of
DOI :
10.1109/JPHOTOV.2014.2371236
