A High Efficiency Si-Ge Based Novel Multijunction Solar Cell

This research is focused on a new type of three junctions high-efficiency solar cell incorporating the promising Si-Ge material as the bottom layer. As a proof of concept, the proposed solar cell has been configured with high-quality material of bandgaps 1.9 eV GaInP2 and 1.42 eV GaAs as top and middle subcells and 0.838 eV bandgap Si0.38Ge0.62 new semiconductor material as bottom subcell. The chosen materials for this configuration are lattice-matched (5.66 Å), and this matching is beneficial for optical transparency and current conductivity. The short circuit current density (Jsc), reverse saturation current density (J0), open-circuit voltage (Voc), voltage (Vm) and current density (Jm) at the maximum power point, fill factor (FF) and the photoconversion efficiency (η) for the proposed multijunction solar cell (MJSC) have been determined by using the standard solar cell equations of modified spectral p-n junction model and MATLAB in-house code. The ASTM G173-03 reference spectra have been utilized for the quantitative analysis at airmass AM1.5G global irradiance condition. The conversion efficiency of the GaInP2/GaAs/Si0.38Ge0.62 solar cell has been simulated as 47.1% at AM1.5G under normal sun (1 sun) concentration and 56.4% under 1000 suns concentration. 

• Research Project