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

Volume

5

Issue

2

fYear

2015

fDate

Mar-15

Firstpage

565

Lastpage

570

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;

fLanguage

English

Journal_Title

Photovoltaics, IEEE Journal of

Publisher

ieee

ISSN

2156-3381

Type

jour

DOI

10.1109/JPHOTOV.2014.2371236

Filename

6996003