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

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

Numerical simulation of graded band gap GaAs/AlGaAs heterojunction solar cell by AMPS-1D

The conduction band discontinuity or spike in an abrupt heterojunction p+ GaAs / NAl0.4 Ga0.6As solar cell can hinder the separation of hole-electron by electric field. This paper analyzes the GaAs /AlxGa1-xAs/Al0.4Ga0.6As based solar cell performance by AMPS-1D numerical modeling. The affect of graded band gap region in the interface between the emitter (GaAs) and base (Al0.4Ga0.6As) on the solar cell’s performance is investigated. Among the factors studied are thickness of graded band gap region, thickness of emitter layer of the cells. In this study, a width 0.14µm has been required to eliminate the spike and improved the performance of solar cell. Keywords: heterojunction solar cell; graded band gap; AMPS-1D

The Effect of Graded Band Gap Structure Inserted in the Multijunction Solar Cell

We have theoretically calculated the photovoltaic conversion efficiency of a monolithic dual-graded junction AlGaAs/GaInAs device, which can be experimentally fabricated. By optimizing the band-gap combination of the considered structure, an improvement of conversion efficiency has been observed in comparison to the conventional AlGaAs/GaInAs system. For the suggested graded band-gap combination, our calculation indicates that the attainable efficiency can be enhanced up to 34% ( AM1.5d). Keywords: band gap gradient, multijunction solar cells, AlGaAs, GaInA