Simulation and optimization of current and lattice matching double-junction GaNAsP/Si solar cells

摘要

This paper deals with theoretical investigation of the performance of current and lattice matched GaN_xAs_yP_(1-x-y)/Si double-junction solar cells. The nitrogen and arsenic concentrations ensuring lattice matching to Si are determined. The band gap of GaNAsP is calculated using the band anti-crossing model. Calculations were performed under 1-sun AM1.5 using the one diode ideal model. Impact of minor carrier lifetime and surface recombination in the top sub-cell on the cell performances is analyzed. Optimum compositions of the top sub-cell have been identified (x = 4.5%, y = 11.5% and E_g = 1.68 eV). The simulation results predict, for the optimized GaNAsP/Si double-junction solar cell, a short circuit current J_(sc) = 20 mA/cm~2, an open circuit voltage V_(oc) = 1.95 V, and a conversion efficiency η = 37.5%.