Search

In this study, the degradation behavior of flexible GaInP/GaAs/InGaAs (IMM3J) solar cells and their metamorphic subcells under 1 MeV electron irradiation was investigated. The remaining factors such as short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power (Pmax) were 95.62, 85.52, and 79.73%, respectively, at an irradiation fluence of 2 × 1015 e/cm2. The spectral responses of the InGaAs and GaAs subcells degraded significantly, and the InGaAs subcell experienced greater degradation than the GaAs subcell after irradiation. In addition, the current-limiting unit was switched from GaInP to InGaAs after irradiation. Defect analysis by deep-level transient spectroscopy (DLTS) revealed that with increasing irradiation fluence, the defects that had the greatest impact on the performance of GaAs subcells were EV + 0.36 and EV + 0.42 eV. For InGaAs subcells, the defects that had the greatest impact on the performance were EV + 0.29 and EV + 0.24 eV. The decrease in the minority carrier lifetime is the main reason for the decrease in the electrical performance of solar cells, and the variation in the effective minority carrier lifetime (τeff) in the subcells with the irradiation fluence was calculated based on the DLTS results. At a fluence of 2 × 1015 e/cm2, the τeff of the GaAs and InGaAs subcells decreased from 2.93 × 10−10 and 9.10 × 10−10 s to 1.56 × 10−11 and 1.60 × 10−12 s, respectively. These results provide a reference for predicting the degradation of short-circuit current and open-circuit voltage of flexible IMM3J. [ABSTRACT FROM AUTHOR]

In this paper, we present an approach to study the electrical and spectral degradation properties of InxGa1-xAs (x = 0.2, 0.3, 0.53) solar cell under 150 keV proton irradiation based on numerical simulation. First, the structures of InxGa1-xAs solar cell were optimized by adjusting the doping concentration of base layer and modifying the thickness of base and emitter layer. The structural parameter related to providing higher conversion efficiency was figured out. Then, the degradation of electrical parameters such as short-circuit current density (Jsc), open-circuit voltage (Voc), maximum output power (Pmax), fill factor (FF), as well as the spectral response were obtained. The degradation correlation with radiation-induced defects was built to reveal the damage mechanism under 150 keV proton irradiation. This study provides constructive model of InxGa1-xAs to be applied in multi-junction solar cells, and the predicted degradation behavior could contribute to design the radiation-hardened space devices. [ABSTRACT FROM AUTHOR]

The degradation characteristic of GaInP/GaAs/In 0.3 Ga 0.7 As inverted metamorphic (IMM) triple junction solar cells irradiated by 1 MeV electron and 10 MeV proton have been studied and compared to that of traditional GaInP/InGaAs/Ge lattice matched (LM) triple junction solar cells. Both IMM and LM solar cells exhibited very good radiation resistance upon 3.16 × 1010 MeV/g displacement damage dose electron and proton irradiation level. The remaining factor of maximum output power is 0.86 and 0.85 for electron irradiation and 0.73 and 0.75 for proton irradiation in IMM and LM solar cells, respectively. IMM solar cell showed better properties in current matching in end-of-life condition comparing to that of LM solar cells. 1 MeV electron to 10 MeV proton irradiation relative damage coefficients, R e p , for IMM and LM solar cells are determined as 3.11 and 2.78, respectively, by using equivalent displacement damage dose model. The radiation damage coefficient of diffusion length upon 1 MeV electron and 10 MeV proton irradiation for both types of solar cell structures have been calculated. • GaInP/GaAs/InGaAs IMM solar cell are studied upon electron and proton irradiation. • Degradation of characteristics of IMM solar cell are compared to LM solar cell. • IMM solar cell showed better properties in current matching in EOL condition. • Relative damage coefficient for electron to proton irradiation have been calculated. • Radiation damage coefficient for minority carrier diffusion length are calculated. [ABSTRACT FROM AUTHOR]

The radiation effects of flexible GaInP/GaAs solar cells under 1 MeV electron irradiation have been studied. GaAs subcell intrinsic layer thickness showed remarkable effects on the solar cell radiation resistance. Based on the integrated current density of subcells, GaAs is determined as the current-limiting subcell before and after irradiation regardless to the i-layer thickness, while GaInP subcell exhibits superior radiation resistance. For 1.5 × 1015 e/cm2 irradiation fluence, the remaining factors of maximum output power are 71.94%, 82.53%, and 82.38%, for GaInP/GaAs solar cells with 0, 0.6 μm, 1.0 μm thick i-layer, respectively. EQE spectra of GaAs subcell degraded more in long-wavelength area, due to the higher defect concentration in the base layer. The flexible GaInP/GaAs dual junction solar cell with 0.6 μm thick i-layer sample exhibited an initial conversion efficiency of 23.79%, and the remaining factor is 82.51% after 1.5 × 1015 e/cm2 fluence electron irradiation. [ABSTRACT FROM AUTHOR]

The zinc (Zn) diffusion effects on metal–organic chemical vapor deposition grown flexible inverted metamorphic (IMM) GaInP/GaAs/InGaAs triple junction solar cell performance have been investigated. By studying electrical and spectral properties of solar cells with different configuration, it was found out that the Zn diffusion from GaAs middle cell AlGaAs:Zn back surface field (BSF) layer into AlGaAs/GaAs tunnel junction is the main reason for I–V curve inflection and low fill factor. Besides, the thermal annealing effects caused by the long epitaxial growth time also has significant effect on Zn diffusion and degrades the overall cell performance. These adverse effects caused by Zn diffusion was suppressed by replacing Zn with carbon as the p-type dopant source in BSF layer, and the thermal annealing effects was solved by fine tuning InGaAs bottom subcell base layer thickness. A large area, 4 × 2 cm2, flexible IMM GaInP/GaAs/InGaAs triple junction solar cell with 34.52% efficiency under AM 1.5D solar spectrum has been successfully fabricated. • Zinc diffusion effects on GaInP/GaAs/InGaAs solar cell have been investigated. • Zn diffusion into tunnel junction is the reason for I–V curve inflection and low FF. • Prolonged epitaxial growth time enhances the Zn diffusion effect. • Zn diffusion effects was suppressed by using carbon as the p-type dopant source. • Cell efficiency increased by adjusting InGaAs bottom subcell base layer thickness. [ABSTRACT FROM AUTHOR]