Degradation analysis of 3J InGaP/InGaAs/InGaAsN solar cell due to irradiation induced defects with a comparative study on bottom homo and hetero InGaAsN subcell

摘要

The influence of irradiation induced traps in the triple junction In0.49Ga0.51P/In0.01Ga0.99As/In0.30Ga0.70As0.98N0.02 solar cell was studied using finite element analysis. The total 3J solar cell structure was simulated separately with homo and hetero InGaAsN structure as the third or bottom subcell. The higher efficient 3J InGaP/InGaAs/InGaAsN solar cell with bottom InGaAsN heterostructure was analyzed by including irradiation induced trap levels. The trap levels correspond to 1 MeV electron irradiation with fluence range of 1 x 10(14)-1 x 10(16) in electrons/cm(2) at room temperature. We realized that the traps in the middle cell cause more degradation, followed by bottom cell and then top cell. The onset of degradation of solar cell parameters (J(sc), V-oc, and eta) starts at trap concentration 1 x 10(13) cm(-3), while more degradation occurs beyond 1 x 10(16) cm(-3). At trap concentration of 1 x 10(16) cm(-3), the solar cell design was optimized for achieving current matching among the subcells. While we obtained 36% conversion efficiency at 1-sun (AMO spectrum) using bottom heterostructure, the introduction of 1 x 10(16) cm(-3) trap concentration and 10(4) cm/s surface recombination velocity simultaneously in all subcells resulted in 20.8% conversion efficiency which increased to 24.3% after current matching.