Study on annealing effects of irradiated Ga0.5In0.5P/GaAs/Ge solar cell by 170 keV proton

In this paper, the degradation and annealing behavior of irradiated Ga_0.5In_0.5P/GaAs/Ge solar cells by 170 keV proton were investigated through light I-V and dark I-V analysis. Ga_0.5In_0.5P/GaAs/Ge solar cells were firstly irradiated by 170 keV proton with faience up to 1×10¹² p/cm² using equivalent ground simulation facility. The results indicated that 170 keV proton irradiation could introduce large amount of vacancies into base region of solar cells, and induce the degradation of light I-V properties of solar cells. The irradiated solar cells were annealed using isothermal annealing technique at 423 K It was shown that after annealing process, the open-circuit voltage (V_oc), short-circuit current (I_sc) and maximum power (P_max) of irradiated Ga₀₅In₀₅P/GaAs/Ge solar cells recovered with annealing time firstly, and then reach to a saturated level. Four parameter including series resistance (R_s), shunt resistance (R_sh), diffusion-junction reverse saturation current (I_sl) and recombination-junction reverse saturation current (I_sc) can be extracted from dark I-V curves of solar cells by non-linear numerical fitting. The results of evolution of light I-V and dark I-V indicated defects in the region near the junction show longer-time annealing dynamic behavior compared with defects in junction region.