Numerical modeling of GaInP/GaAs monolithic tandem solar cells

In this work, we present simulation of a monolithic tandem GaInP/GaAs solar cell made from a top GaInP cell and a bottom GaAs cell. For this purpose we used one dimensional simulation program tool called Solar Cell Capacitance Simulator in one Dimension (SCAPS-1D), the proposed methodology consists of simulating each cell separately. For enhanced electric characteristics of a tandem solar cell, the current-match condition between the top and bottom cells should be satisfied, which in turn requires careful design of the tandem parameters. To fulfill this condition, the top cell base thickness of (GaInP) is adjusted accordingly. The solar spectrum reaching the lower cell is computed by subtracting the top cell spectrum from the total solar spectrum. The optimal value of the short circuit current density corresponds to a top cell’s base thickness of 0.7 μm; this results in an open circuit voltage of 2.397 V, a short circuit current density of 13.87 mA/cm2, an efficiency of 29.83 % and a fill factor of 89.74 % under the AM1.5G solar spectrum.