Optimization of a Tandem Solar Cell GaAs / Ge using AMPS-1D

Abstract

The  primary  objective  of  this  modeling  investigation  is  to  optimize  a  multi-junction tandem  device under  the AM1.5G  spectrum. Based on previous studies, GaAs and Ge cells, because of their energy band gaps, can be combined together to achieve high-efficiency double-junction devices. In this study, the top cell is made of GaAs (1.42 eV) while the bottom cell is made of Ge (0.66 eV). In order to avoid the losses and design constraints observed in two-terminal and four-terminal devices.

In order to determine the optimal structure of the device,  the top and bottom junctions were investigated and  optimized with regard to the thicknesses . The optimum configuration of the device shows an efficiency of 32.07% under the AM1.5G spectrum and one sun, which is higher than the efficiency of an optimized single-junction Si cell under the same illumination conditions.

Keywords: AMPS-1D, multi-junction, Ge, GaAs, optimization.